diff --git a/apps/desktop/scripts/electron-launcher.mjs b/apps/desktop/scripts/electron-launcher.mjs
index 081ef903a066..929afeeabe9c 100644
--- a/apps/desktop/scripts/electron-launcher.mjs
+++ b/apps/desktop/scripts/electron-launcher.mjs
@@ -20,7 +20,7 @@ export const APP_BUNDLE_ID = isDevelopment
   ? `com.t3tools.t3code.dev.${devBundleIdSuffix || "local"}`
   : "com.t3tools.t3code";
 const APP_PROTOCOL_SCHEMES = isDevelopment ? ["t3code-dev"] : ["t3code"];
-const LAUNCHER_VERSION = 12;
+const LAUNCHER_VERSION = 14;
 const defaultIconPath = NodePath.join(desktopDir, "resources", "icon.icns");
 const developmentMacIconPngPath = NodePath.join(
   repoRoot,
@@ -220,11 +220,12 @@ function ensureDevelopmentIconIcns(runtimeDir) {
   }
 }
 
-function patchMainBundleInfoPlist(appBundlePath, iconPath) {
+function patchMainBundleInfoPlist(appBundlePath, iconPath, executableName) {
   const infoPlistPath = NodePath.join(appBundlePath, "Contents", "Info.plist");
   setPlistString(infoPlistPath, "CFBundleDisplayName", APP_DISPLAY_NAME);
   setPlistString(infoPlistPath, "CFBundleName", APP_DISPLAY_NAME);
   setPlistString(infoPlistPath, "CFBundleIdentifier", APP_BUNDLE_ID);
+  setPlistString(infoPlistPath, "CFBundleExecutable", executableName);
   setPlistString(infoPlistPath, "CFBundleIconFile", "icon.icns");
   setPlistJson(infoPlistPath, "CFBundleURLTypes", [
     {
@@ -277,11 +278,25 @@ function readJson(path) {
   }
 }
 
+export function resolveMacLauncherPaths(appBundlePath, displayName = APP_DISPLAY_NAME) {
+  const executableDir = NodePath.join(appBundlePath, "Contents", "MacOS");
+  const launcherExecutableName = `${displayName} Launcher`;
+  return {
+    launcherExecutableName,
+    launcherBinaryPath: NodePath.join(executableDir, launcherExecutableName),
+    runtimeElectronBinaryPath: NodePath.join(executableDir, "Electron"),
+  };
+}
+
 function buildMacLauncher(electronBinaryPath) {
   const sourceAppBundlePath = NodePath.resolve(NodePath.dirname(electronBinaryPath), "../..");
   const runtimeDir = NodePath.join(desktopDir, ".electron-runtime");
   const targetAppBundlePath = NodePath.join(runtimeDir, `${APP_DISPLAY_NAME}.app`);
-  const targetBinaryPath = NodePath.join(targetAppBundlePath, "Contents", "MacOS", "Electron");
+  const developmentPaths = resolveMacLauncherPaths(targetAppBundlePath);
+  const runtimeElectronBinaryPath = developmentPaths.runtimeElectronBinaryPath;
+  const launcherBinaryPath = isDevelopment
+    ? developmentPaths.launcherBinaryPath
+    : runtimeElectronBinaryPath;
   const iconPath = isDevelopment ? ensureDevelopmentIconIcns(runtimeDir) : defaultIconPath;
   const metadataPath = NodePath.join(runtimeDir, "metadata.json");
 
@@ -298,7 +313,8 @@ function buildMacLauncher(electronBinaryPath) {
 
   const currentMetadata = readJson(metadataPath);
   if (
-    NodeFS.existsSync(targetBinaryPath) &&
+    NodeFS.existsSync(launcherBinaryPath) &&
+    (!isDevelopment || NodeFS.existsSync(runtimeElectronBinaryPath)) &&
     currentMetadata &&
     JSON.stringify(currentMetadata) === JSON.stringify(expectedMetadata)
   ) {
@@ -306,10 +322,10 @@ function buildMacLauncher(electronBinaryPath) {
       // The launcher also handles protocol activations outside the dev runner,
       // so refresh its fallback environment on every launch. Never let a value
       // captured by an older parent app override the live dev-runner environment.
-      writeDevelopmentLauncherScript(targetBinaryPath, electronBinaryPath);
+      writeDevelopmentLauncherScript(launcherBinaryPath, runtimeElectronBinaryPath);
     }
     registerMacLauncherBundle(targetAppBundlePath);
-    return targetBinaryPath;
+    return launcherBinaryPath;
   }
 
   NodeFS.rmSync(targetAppBundlePath, { recursive: true, force: true });
@@ -321,15 +337,24 @@ function buildMacLauncher(electronBinaryPath) {
     recursive: true,
     verbatimSymlinks: true,
   });
-  patchMainBundleInfoPlist(targetAppBundlePath, iconPath);
+  patchMainBundleInfoPlist(
+    targetAppBundlePath,
+    iconPath,
+    isDevelopment ? developmentPaths.launcherExecutableName : "Electron",
+  );
   patchHelperBundleInfoPlists(targetAppBundlePath);
   if (isDevelopment) {
-    writeDevelopmentLauncherScript(targetBinaryPath, electronBinaryPath);
+    // Keep Electron's native executable inside the branded bundle. Launching the
+    // node_modules copy makes macOS associate the process (and Dock label) with
+    // Electron.app even though this bundle's Info.plist has the T3 Code name.
+    // Its conventional executable name also keeps Electron's default-app runtime
+    // in development mode instead of making app.isPackaged report true.
+    writeDevelopmentLauncherScript(launcherBinaryPath, runtimeElectronBinaryPath);
   }
   NodeFS.writeFileSync(metadataPath, `${JSON.stringify(expectedMetadata, null, 2)}\n`);
   registerMacLauncherBundle(targetAppBundlePath);
 
-  return targetBinaryPath;
+  return launcherBinaryPath;
 }
 
 function isLinuxSetuidSandboxConfigured(electronBinaryPath) {
diff --git a/apps/desktop/scripts/electron-launcher.test.mjs b/apps/desktop/scripts/electron-launcher.test.mjs
index 36e9429e4446..1c82167ea217 100644
--- a/apps/desktop/scripts/electron-launcher.test.mjs
+++ b/apps/desktop/scripts/electron-launcher.test.mjs
@@ -1,6 +1,10 @@
 import { assert, describe, it } from "vite-plus/test";
 
-import { makeDevelopmentLauncherScript, resolveElectronBinaryPath } from "./electron-launcher.mjs";
+import {
+  makeDevelopmentLauncherScript,
+  resolveElectronBinaryPath,
+  resolveMacLauncherPaths,
+} from "./electron-launcher.mjs";
 
 describe("electron development launcher", () => {
   it("uses captured values only as fallbacks for a live runner environment", () => {
@@ -45,4 +49,33 @@ describe("electron development launcher", () => {
     );
     assert.deepEqual(calls, ["ensure", "require:electron"]);
   });
+
+  it("keeps the native Electron executable name inside the branded macOS bundle", () => {
+    const paths = resolveMacLauncherPaths(
+      "/repo/apps/desktop/.electron-runtime/T3 Code (Dev).app",
+      "T3 Code (Dev)",
+    );
+
+    assert.equal(paths.launcherExecutableName, "T3 Code (Dev) Launcher");
+    assert.equal(
+      paths.launcherBinaryPath,
+      "/repo/apps/desktop/.electron-runtime/T3 Code (Dev).app/Contents/MacOS/T3 Code (Dev) Launcher",
+    );
+    assert.equal(
+      paths.runtimeElectronBinaryPath,
+      "/repo/apps/desktop/.electron-runtime/T3 Code (Dev).app/Contents/MacOS/Electron",
+    );
+
+    const script = makeDevelopmentLauncherScript({
+      electronBinaryPath: paths.runtimeElectronBinaryPath,
+      mainEntryPath: "/repo/apps/desktop/dist-electron/main.cjs",
+      desktopRoot: "/repo/apps/desktop",
+      environment: {},
+    });
+    assert.include(
+      script,
+      "exec '/repo/apps/desktop/.electron-runtime/T3 Code (Dev).app/Contents/MacOS/Electron'",
+    );
+    assert.notInclude(script, "node_modules/electron");
+  });
 });
diff --git a/apps/desktop/src/electron/ElectronUpdater.test.ts b/apps/desktop/src/electron/ElectronUpdater.test.ts
index 8fcc34f41c24..c2acc9ce120a 100644
--- a/apps/desktop/src/electron/ElectronUpdater.test.ts
+++ b/apps/desktop/src/electron/ElectronUpdater.test.ts
@@ -10,6 +10,7 @@ const { autoUpdaterMock } = vi.hoisted(() => ({
     autoInstallOnAppQuit: true,
     channel: "latest",
     disableDifferentialDownload: false,
+    fullChangelog: false,
     checkForUpdates: vi.fn(() => Promise.resolve(null)),
     downloadUpdate: vi.fn(() => Promise.resolve([])),
     on: vi.fn(),
@@ -33,6 +34,7 @@ describe("ElectronUpdater", () => {
     autoUpdaterMock.autoInstallOnAppQuit = true;
     autoUpdaterMock.channel = "latest";
     autoUpdaterMock.disableDifferentialDownload = false;
+    autoUpdaterMock.fullChangelog = false;
     autoUpdaterMock.checkForUpdates.mockClear();
     autoUpdaterMock.checkForUpdates.mockImplementation(() => Promise.resolve(null));
     autoUpdaterMock.downloadUpdate.mockClear();
@@ -98,6 +100,18 @@ describe("ElectronUpdater", () => {
     }).pipe(Effect.provide(ElectronUpdater.layer)),
   );
 
+  it.effect("sets full changelog mode", () =>
+    Effect.gen(function* () {
+      const updater = yield* ElectronUpdater.ElectronUpdater;
+
+      yield* updater.setFullChangelog(true);
+      assert.equal(autoUpdaterMock.fullChangelog, true);
+
+      yield* updater.setFullChangelog(false);
+      assert.equal(autoUpdaterMock.fullChangelog, false);
+    }).pipe(Effect.provide(ElectronUpdater.layer)),
+  );
+
   it.effect("preserves quit-and-install flags and the execution-time channel", () =>
     Effect.gen(function* () {
       const cause = new Error("quit and install failed");
diff --git a/apps/desktop/src/electron/ElectronUpdater.ts b/apps/desktop/src/electron/ElectronUpdater.ts
index 435fbd002289..4157d29a9df8 100644
--- a/apps/desktop/src/electron/ElectronUpdater.ts
+++ b/apps/desktop/src/electron/ElectronUpdater.ts
@@ -66,6 +66,7 @@ export class ElectronUpdater extends Context.Service<
     readonly setAllowPrerelease: (value: boolean) => Effect.Effect<void>;
     readonly allowDowngrade: Effect.Effect<boolean>;
     readonly setAllowDowngrade: (value: boolean) => Effect.Effect<void>;
+    readonly setFullChangelog: (value: boolean) => Effect.Effect<void>;
     readonly setDisableDifferentialDownload: (value: boolean) => Effect.Effect<void>;
     readonly checkForUpdates: Effect.Effect<void, ElectronUpdaterCheckForUpdatesError>;
     readonly downloadUpdate: Effect.Effect<void, ElectronUpdaterDownloadUpdateError>;
@@ -112,6 +113,11 @@ export const make = ElectronUpdater.of({
       autoUpdater.allowDowngrade = value;
       return Effect.void;
     }),
+  setFullChangelog: (value) =>
+    Effect.suspend(() => {
+      autoUpdater.fullChangelog = value;
+      return Effect.void;
+    }),
   setDisableDifferentialDownload: (value) =>
     Effect.suspend(() => {
       autoUpdater.disableDifferentialDownload = value;
diff --git a/apps/desktop/src/updates/DesktopUpdates.test.ts b/apps/desktop/src/updates/DesktopUpdates.test.ts
index 696bd755506b..5ae92bbee963 100644
--- a/apps/desktop/src/updates/DesktopUpdates.test.ts
+++ b/apps/desktop/src/updates/DesktopUpdates.test.ts
@@ -38,6 +38,7 @@ const flushCallbacks = Effect.yieldNow;
 function makeHarness(options: UpdatesHarnessOptions = {}) {
   let checkCount = 0;
   let allowDowngrade = false;
+  let fullChangelog = false;
   const feedUrls: ElectronUpdater.ElectronUpdaterFeedUrl[] = [];
   const listeners = new Map<string, Set<(...args: readonly unknown[]) => void>>();
   const sentStates: DesktopUpdateState[] = [];
@@ -73,6 +74,10 @@ function makeHarness(options: UpdatesHarnessOptions = {}) {
       Effect.sync(() => {
         allowDowngrade = value;
       }),
+    setFullChangelog: (value) =>
+      Effect.sync(() => {
+        fullChangelog = value;
+      }),
     setDisableDifferentialDownload: () => options.setDisableDifferentialDownload ?? Effect.void,
     checkForUpdates: Effect.sync(() => {
       checkCount += 1;
@@ -186,6 +191,7 @@ function makeHarness(options: UpdatesHarnessOptions = {}) {
     layer,
     checkCount: () => checkCount,
     feedUrls: () => feedUrls,
+    fullChangelog: () => fullChangelog,
     listenerCount: () =>
       Array.from(listeners.values()).reduce(
         (total, eventListeners) => total + eventListeners.size,
@@ -287,6 +293,49 @@ describe("DesktopUpdates", () => {
     ).pipe(Effect.provide(Layer.merge(TestClock.layer(), harness.layer)));
   });
 
+  it.effect("enables nightly full changelog release notes and broadcasts summaries", () => {
+    const harness = makeHarness();
+
+    return Effect.scoped(
+      Effect.gen(function* () {
+        const updates = yield* DesktopUpdates.DesktopUpdates;
+        yield* updates.configure;
+
+        yield* updates.setChannel("nightly");
+        assert.equal(harness.fullChangelog(), true);
+
+        harness.emit("update-available", {
+          version: "1.2.4-nightly.20260709.766",
+          releaseNotes: [
+            {
+              version: "1.2.4-nightly.20260709.766",
+              note: `<h2>What's Changed</h2><ul><li>feat(client): persist offline environment data by <a>@juliusmarminge</a> in <a>#3795</a></li></ul><h2>Full Changelog</h2>`,
+            },
+            {
+              version: "1.2.4-nightly.20260709.765",
+              note: "- [codex] Upgrade Clerk stack by @juliusmarminge in #3821",
+            },
+          ],
+        });
+        yield* flushCallbacks;
+
+        const state = yield* updates.getState;
+        assert.equal(state.status, "available");
+        assert.deepEqual(state.releaseNotes, [
+          {
+            version: "1.2.4-nightly.20260709.766",
+            items: ["feat(client): persist offline environment data by @juliusmarminge in #3795"],
+          },
+          {
+            version: "1.2.4-nightly.20260709.765",
+            items: ["[codex] Upgrade Clerk stack by @juliusmarminge in #3821"],
+          },
+        ]);
+        assert.deepEqual(harness.sentStates.at(-1)?.releaseNotes, state.releaseNotes);
+      }),
+    ).pipe(Effect.provide(Layer.merge(TestClock.layer(), harness.layer)));
+  });
+
   it.effect("keeps raw updater event failures out of update state", () => {
     const harness = makeHarness();
     const cause = new Error(
diff --git a/apps/desktop/src/updates/DesktopUpdates.ts b/apps/desktop/src/updates/DesktopUpdates.ts
index aabb0830b0f8..7357907e1783 100644
--- a/apps/desktop/src/updates/DesktopUpdates.ts
+++ b/apps/desktop/src/updates/DesktopUpdates.ts
@@ -27,6 +27,7 @@ import * as ElectronUpdater from "../electron/ElectronUpdater.ts";
 import * as ElectronWindow from "../electron/ElectronWindow.ts";
 import * as IpcChannels from "../ipc/channels.ts";
 import * as DesktopAppSettings from "../settings/DesktopAppSettings.ts";
+import { normalizeDesktopUpdateReleaseNotes } from "./releaseNotes.ts";
 import { resolveDefaultDesktopUpdateChannel } from "./updateChannels.ts";
 import {
   createInitialDesktopUpdateState,
@@ -49,6 +50,10 @@ type AppUpdateYmlConfig = typeof AppUpdateYmlConfig.Type;
 
 const UpdateInfo = Schema.Struct({
   version: Schema.String,
+  // Left unvalidated on purpose: a malformed release-notes payload must never
+  // fail the decode and block the update state transition. The shape is
+  // validated defensively in normalizeDesktopUpdateReleaseNotes.
+  releaseNotes: Schema.optional(Schema.Unknown),
 });
 
 const DownloadProgressInfo = Schema.Struct({
@@ -330,10 +335,12 @@ export const make = Effect.gen(function* () {
     yield* electronUpdater.setChannel(channel);
     yield* electronUpdater.setAllowPrerelease(allowsPrerelease);
     yield* electronUpdater.setAllowDowngrade(allowsPrerelease);
+    yield* electronUpdater.setFullChangelog(allowsPrerelease);
     yield* logUpdaterInfo("using update channel", {
       channel,
       allowPrerelease: allowsPrerelease,
       allowDowngrade: allowsPrerelease,
+      fullChangelog: allowsPrerelease,
     });
   });
 
@@ -567,11 +574,15 @@ export const make = Effect.gen(function* () {
           }
 
           const checkedAt = yield* currentIsoTimestamp;
+          const releaseNotes = normalizeDesktopUpdateReleaseNotes(info.releaseNotes, info.version);
           yield* setState(
-            reduceDesktopUpdateStateOnUpdateAvailable(state, info.version, checkedAt),
+            reduceDesktopUpdateStateOnUpdateAvailable(state, info.version, checkedAt, releaseNotes),
           );
           yield* Ref.set(lastLoggedDownloadMilestoneRef, -1);
-          yield* logUpdaterInfo("update available", { version: info.version });
+          yield* logUpdaterInfo("update available", {
+            version: info.version,
+            releaseNoteGroups: releaseNotes.length,
+          });
         }),
       ),
       Effect.catchCause((cause) => {
diff --git a/apps/desktop/src/updates/releaseNotes.test.ts b/apps/desktop/src/updates/releaseNotes.test.ts
new file mode 100644
index 000000000000..9d6bbaea6bcb
--- /dev/null
+++ b/apps/desktop/src/updates/releaseNotes.test.ts
@@ -0,0 +1,67 @@
+import { describe, expect, it } from "vite-plus/test";
+
+import { normalizeDesktopUpdateReleaseNotes } from "./releaseNotes.ts";
+
+describe("normalizeDesktopUpdateReleaseNotes", () => {
+  it("splits a plain string note into items under the fallback version", () => {
+    const notes = normalizeDesktopUpdateReleaseNotes(
+      "## What's changed\n- First fix\n- Second fix",
+      "1.2.3",
+    );
+    expect(notes).toEqual([{ version: "1.2.3", items: ["First fix", "Second fix"] }]);
+  });
+
+  it("keeps per-version groups and drops empty ones", () => {
+    const notes = normalizeDesktopUpdateReleaseNotes(
+      [
+        { version: "1.2.3", note: "- Newer change" },
+        { version: "1.2.2", note: "Full changelog: https://example.com/compare/x...y" },
+        { version: "1.2.1", note: "- Older change" },
+      ],
+      "1.2.3",
+    );
+    expect(notes).toEqual([
+      { version: "1.2.3", items: ["Newer change"] },
+      { version: "1.2.1", items: ["Older change"] },
+    ]);
+  });
+
+  it("decodes valid HTML entities", () => {
+    const notes = normalizeDesktopUpdateReleaseNotes("- Fix &amp; polish &#128512;", "1.0.0");
+    expect(notes).toEqual([{ version: "1.0.0", items: ["Fix & polish 😀"] }]);
+  });
+
+  it("ignores malformed entries instead of throwing", () => {
+    const notes = normalizeDesktopUpdateReleaseNotes(
+      [
+        { version: "1.2.3", note: "- Valid change" },
+        { version: 42, note: "- Bad version type" },
+        { version: "1.2.1", note: { html: "<p>object note</p>" } },
+        "not an object",
+        null,
+      ],
+      "1.2.3",
+    );
+    expect(notes).toEqual([{ version: "1.2.3", items: ["Valid change"] }]);
+  });
+
+  it("returns non-empty groups even when preceded by many boilerplate-only groups", () => {
+    const boilerplate = Array.from({ length: 7 }, (_, index) => ({
+      version: `1.3.${9 - index}`,
+      note: "Full changelog: https://example.com/compare/x...y",
+    }));
+    const notes = normalizeDesktopUpdateReleaseNotes(
+      [...boilerplate, { version: "1.3.2", note: "- Older but real change" }],
+      "1.3.9",
+    );
+    expect(notes).toEqual([{ version: "1.3.2", items: ["Older but real change"] }]);
+  });
+
+  it("does not throw on out-of-range numeric entities and keeps the literal", () => {
+    expect(() =>
+      normalizeDesktopUpdateReleaseNotes("- Broken entity &#9999999999;", "1.0.0"),
+    ).not.toThrow();
+    const notes = normalizeDesktopUpdateReleaseNotes("- Broken entity &#9999999999;", "1.0.0");
+    expect(notes).toEqual([{ version: "1.0.0", items: ["Broken entity &#9999999999;"] }]);
+  });
+});
diff --git a/apps/desktop/src/updates/releaseNotes.ts b/apps/desktop/src/updates/releaseNotes.ts
new file mode 100644
index 000000000000..69857c92b3f1
--- /dev/null
+++ b/apps/desktop/src/updates/releaseNotes.ts
@@ -0,0 +1,125 @@
+import type { DesktopUpdateReleaseNote } from "@t3tools/contracts";
+
+interface ElectronReleaseNoteInfo {
+  readonly version: string;
+  readonly note: string | null | undefined;
+}
+
+function isElectronReleaseNoteInfo(value: unknown): value is ElectronReleaseNoteInfo {
+  if (typeof value !== "object" || value === null) return false;
+  const candidate = value as { readonly version?: unknown; readonly note?: unknown };
+  return (
+    typeof candidate.version === "string" &&
+    (typeof candidate.note === "string" || candidate.note === null || candidate.note === undefined)
+  );
+}
+
+const MAX_RELEASE_NOTE_GROUPS = 6;
+const MAX_RELEASE_NOTE_ITEMS_PER_GROUP = 8;
+const MAX_RELEASE_NOTE_ITEM_LENGTH = 220;
+
+const HTML_ENTITY_REPLACEMENTS: Readonly<Record<string, string>> = {
+  amp: "&",
+  apos: "'",
+  gt: ">",
+  lt: "<",
+  nbsp: " ",
+  quot: '"',
+};
+
+function decodeCodePoint(codePoint: number, entity: string): string {
+  // String.fromCodePoint throws RangeError outside the valid Unicode range, and
+  // Number.isFinite alone lets oversized values (e.g. &#9999999999;) through.
+  if (!Number.isInteger(codePoint) || codePoint < 0 || codePoint > 0x10ffff) {
+    return `&${entity};`;
+  }
+  return String.fromCodePoint(codePoint);
+}
+
+function decodeHtmlEntity(entity: string): string {
+  const named = HTML_ENTITY_REPLACEMENTS[entity];
+  if (named) return named;
+  if (entity.startsWith("#x")) {
+    return decodeCodePoint(Number.parseInt(entity.slice(2), 16), entity);
+  }
+  if (entity.startsWith("#")) {
+    return decodeCodePoint(Number.parseInt(entity.slice(1), 10), entity);
+  }
+  return `&${entity};`;
+}
+
+function decodeHtmlEntities(input: string): string {
+  return input.replace(/&([a-zA-Z]+|#\d+|#x[0-9a-fA-F]+);/g, (_, entity: string) =>
+    decodeHtmlEntity(entity),
+  );
+}
+
+function stripMarkup(input: string): string {
+  return decodeHtmlEntities(
+    input
+      .replace(/<br\s*\/?>/gi, "\n")
+      .replace(/<li\b[^>]*>/gi, "\n- ")
+      .replace(/<\/(?:p|div|li|h[1-6]|ul|ol|blockquote)>/gi, "\n")
+      .replace(/<[^>]*>/g, "")
+      .replace(/\[([^\]]+)\]\([^)]+\)/g, "$1")
+      .replace(/\*\*([^*]+)\*\*/g, "$1"),
+  );
+}
+
+function truncateReleaseNoteItem(item: string): string {
+  if (item.length <= MAX_RELEASE_NOTE_ITEM_LENGTH) return item;
+  return `${item.slice(0, MAX_RELEASE_NOTE_ITEM_LENGTH - 3).trimEnd()}...`;
+}
+
+function isIgnoredReleaseNoteLine(line: string): boolean {
+  const normalized = line
+    .toLowerCase()
+    .replace(/[*_`#]/g, "")
+    .trim();
+  return (
+    normalized === "" ||
+    normalized === "what's changed" ||
+    normalized === "whats changed" ||
+    normalized === "full changelog" ||
+    normalized === "new contributors" ||
+    normalized.startsWith("compare: ") ||
+    normalized.includes("/compare/")
+  );
+}
+
+function extractReleaseNoteItems(note: string | null | undefined): ReadonlyArray<string> {
+  if (!note) return [];
+
+  const items: string[] = [];
+  for (const rawLine of stripMarkup(note).split("\n")) {
+    const item = rawLine
+      .trim()
+      .replace(/^[-*]\s+/, "")
+      .replace(/^\d+[.)]\s+/, "")
+      .replace(/\s+/g, " ");
+    if (isIgnoredReleaseNoteLine(item)) continue;
+    items.push(truncateReleaseNoteItem(item));
+    if (items.length >= MAX_RELEASE_NOTE_ITEMS_PER_GROUP) break;
+  }
+  return items;
+}
+
+export function normalizeDesktopUpdateReleaseNotes(
+  releaseNotes: unknown,
+  fallbackVersion: string,
+): ReadonlyArray<DesktopUpdateReleaseNote> {
+  const rawNotes =
+    typeof releaseNotes === "string"
+      ? [{ version: fallbackVersion, note: releaseNotes }]
+      : Array.isArray(releaseNotes)
+        ? releaseNotes.filter(isElectronReleaseNoteInfo)
+        : [];
+
+  return rawNotes
+    .map((entry) => ({
+      version: entry.version,
+      items: extractReleaseNoteItems(entry.note),
+    }))
+    .filter((entry) => entry.items.length > 0)
+    .slice(0, MAX_RELEASE_NOTE_GROUPS);
+}
diff --git a/apps/desktop/src/updates/updateMachine.test.ts b/apps/desktop/src/updates/updateMachine.test.ts
index 4b2a87c7ce0c..040411f76f4f 100644
--- a/apps/desktop/src/updates/updateMachine.test.ts
+++ b/apps/desktop/src/updates/updateMachine.test.ts
@@ -118,6 +118,12 @@ describe("updateMachine", () => {
   });
 
   it("tracks available, download start, and progress cleanly", () => {
+    const releaseNotes = [
+      {
+        version: "1.1.0",
+        items: ["feat: add update release notes"],
+      },
+    ];
     const available = reduceDesktopUpdateStateOnUpdateAvailable(
       {
         ...createInitialDesktopUpdateState("1.0.0", runtimeInfo, "latest"),
@@ -126,15 +132,33 @@ describe("updateMachine", () => {
       },
       "1.1.0",
       "2026-03-04T00:00:00.000Z",
+      releaseNotes,
     );
     const downloading = reduceDesktopUpdateStateOnDownloadStart(available);
     const progress = reduceDesktopUpdateStateOnDownloadProgress(downloading, 55.5);
 
     expect(available.status).toBe("available");
     expect(available.channel).toBe("latest");
+    expect(available.releaseNotes).toBe(releaseNotes);
+    expect(downloading.releaseNotes).toBe(releaseNotes);
     expect(downloading.status).toBe("downloading");
     expect(downloading.downloadPercent).toBe(0);
     expect(progress.downloadPercent).toBe(55.5);
     expect(progress.errorContext).toBeNull();
   });
+
+  it("clears release notes when checking again", () => {
+    const state = reduceDesktopUpdateStateOnCheckStart(
+      {
+        ...createInitialDesktopUpdateState("1.0.0", runtimeInfo, "nightly"),
+        enabled: true,
+        status: "available",
+        availableVersion: "1.1.0-nightly.1",
+        releaseNotes: [{ version: "1.1.0-nightly.1", items: ["feat: old note"] }],
+      },
+      "2026-03-04T00:00:00.000Z",
+    );
+
+    expect(state.releaseNotes).toEqual([]);
+  });
 });
diff --git a/apps/desktop/src/updates/updateMachine.ts b/apps/desktop/src/updates/updateMachine.ts
index b5037225774b..fef51bbb8ab2 100644
--- a/apps/desktop/src/updates/updateMachine.ts
+++ b/apps/desktop/src/updates/updateMachine.ts
@@ -1,6 +1,7 @@
 import type {
   DesktopRuntimeInfo,
   DesktopUpdateChannel,
+  DesktopUpdateReleaseNote,
   DesktopUpdateState,
 } from "@t3tools/contracts";
 
@@ -29,6 +30,7 @@ export function createInitialDesktopUpdateState(
     runningUnderArm64Translation: runtimeInfo.runningUnderArm64Translation,
     availableVersion: null,
     downloadedVersion: null,
+    releaseNotes: [],
     downloadPercent: null,
     checkedAt: null,
     message: null,
@@ -45,6 +47,7 @@ export function reduceDesktopUpdateStateOnCheckStart(
     ...state,
     status: "checking",
     checkedAt,
+    releaseNotes: [],
     message: null,
     downloadPercent: null,
     errorContext: null,
@@ -72,12 +75,14 @@ export function reduceDesktopUpdateStateOnUpdateAvailable(
   state: DesktopUpdateState,
   version: string,
   checkedAt: string,
+  releaseNotes: ReadonlyArray<DesktopUpdateReleaseNote> = [],
 ): DesktopUpdateState {
   return {
     ...state,
     status: "available",
     availableVersion: version,
     downloadedVersion: null,
+    releaseNotes,
     downloadPercent: null,
     checkedAt,
     message: null,
@@ -95,6 +100,7 @@ export function reduceDesktopUpdateStateOnNoUpdate(
     status: "up-to-date",
     availableVersion: null,
     downloadedVersion: null,
+    releaseNotes: [],
     downloadPercent: null,
     checkedAt,
     message: null,
diff --git a/apps/marketing/public/harnesses/cursor_light.svg b/apps/marketing/public/harnesses/cursor_light.svg
index e61e0be3bfdd..089d4676370b 100644
--- a/apps/marketing/public/harnesses/cursor_light.svg
+++ b/apps/marketing/public/harnesses/cursor_light.svg
@@ -1 +1 @@
-<?xml version="1.0" encoding="UTF-8"?><svg id="cursor_light__Ebene_1" xmlns="http://www.w3.org/2000/svg" version="1.1" viewBox="0 0 466.73 532.09"><defs></defs><path class="cursor_light__st0" d="M457.43,125.94L244.42,2.96c-6.84-3.95-15.28-3.95-22.12,0L9.3,125.94c-5.75,3.32-9.3,9.46-9.3,16.11v247.99c0,6.65,3.55,12.79,9.3,16.11l213.01,122.98c6.84,3.95,15.28,3.95,22.12,0l213.01-122.98c5.75-3.32,9.3-9.46,9.3-16.11v-247.99c0-6.65-3.55-12.79-9.3-16.11h-.01ZM444.05,151.99l-205.63,356.16c-1.39,2.4-5.06,1.42-5.06-1.36v-233.21c0-4.66-2.49-8.97-6.53-11.31L24.87,145.67c-2.4-1.39-1.42-5.06,1.36-5.06h411.26c5.84,0,9.49,6.33,6.57,11.39h-.01Z"></path></svg>
\ No newline at end of file
+<?xml version="1.0" encoding="UTF-8"?><svg id="cursor_light__Ebene_1" xmlns="http://www.w3.org/2000/svg" version="1.1" viewBox="0 0 466.73 532.09"><defs></defs><path class="cursor_light__st0" fill="#EDECEC" d="M457.43,125.94L244.42,2.96c-6.84-3.95-15.28-3.95-22.12,0L9.3,125.94c-5.75,3.32-9.3,9.46-9.3,16.11v247.99c0,6.65,3.55,12.79,9.3,16.11l213.01,122.98c6.84,3.95,15.28,3.95,22.12,0l213.01-122.98c5.75-3.32,9.3-9.46,9.3-16.11v-247.99c0-6.65-3.55-12.79-9.3-16.11h-.01ZM444.05,151.99l-205.63,356.16c-1.39,2.4-5.06,1.42-5.06-1.36v-233.21c0-4.66-2.49-8.97-6.53-11.31L24.87,145.67c-2.4-1.39-1.42-5.06,1.36-5.06h411.26c5.84,0,9.49,6.33,6.57,11.39h-.01Z"></path></svg>
diff --git a/apps/marketing/src/lib/site.ts b/apps/marketing/src/lib/site.ts
index 5ff5958c588f..92e491a077a7 100644
--- a/apps/marketing/src/lib/site.ts
+++ b/apps/marketing/src/lib/site.ts
@@ -1,6 +1,6 @@
 export const GITHUB_REPOSITORY_URL = "https://github.com/pingdotgg/t3code";
 
 export const MARKETING_STATS = {
-  githubStars: "12k+",
+  githubStars: "14k+",
   users: "100,000",
 } as const;
diff --git a/apps/mobile/app.config.ts b/apps/mobile/app.config.ts
index fd7a93884159..d1c29ffcfc6e 100644
--- a/apps/mobile/app.config.ts
+++ b/apps/mobile/app.config.ts
@@ -1,5 +1,6 @@
 import type { ExpoConfig } from "expo/config";
 
+import { BRAND_ASSET_PATHS } from "../../scripts/lib/brand-assets.ts";
 import { loadRepoEnv } from "../../scripts/lib/public-config.ts";
 
 type AppVariant = "development" | "preview" | "production";
@@ -15,6 +16,8 @@ const isIosPersonalTeamBuild = repoEnv.T3CODE_IOS_PERSONAL_TEAM === "1";
 const personalTeamBundleIdentifier = repoEnv.T3CODE_IOS_PERSONAL_TEAM_BUNDLE_ID?.trim();
 const IOS_BUNDLE_IDENTIFIER_PATTERN = /^[A-Za-z0-9-]+(?:\.[A-Za-z0-9-]+)+$/;
 
+const fromRepoRoot = (relativePath: string) => `../../${relativePath}`;
+
 if (
   isIosPersonalTeamBuild &&
   (!personalTeamBundleIdentifier ||
@@ -26,20 +29,31 @@ if (
 }
 
 const DEVELOPMENT_ASSETS = {
-  appIcon: "./assets/splash-icon-dev.png",
-  iosIcon: "./assets/icon-composer-dev.icon",
-  splashIcon: "./assets/splash-icon-dev.png",
-  androidAdaptiveForeground: "./assets/android-icon-dev-foreground.png",
+  appIcon: fromRepoRoot(BRAND_ASSET_PATHS.developmentIosIconPng),
+  iosIcon: fromRepoRoot(BRAND_ASSET_PATHS.developmentIconComposerProject),
+  splashIcon: fromRepoRoot(BRAND_ASSET_PATHS.developmentIosIconPng),
+  androidAdaptiveForeground: fromRepoRoot(BRAND_ASSET_PATHS.developmentUniversalIconPng),
   androidAdaptiveBackgroundColor: "#00639B",
   androidMonochromeIcon: "./assets/android-icon-mark.png",
   androidNotificationIcon: "./assets/android-notification-icon.png",
   androidNotificationColor: "#00639B",
 } as const;
 
+const PREVIEW_ASSETS = {
+  appIcon: fromRepoRoot(BRAND_ASSET_PATHS.nightlyIosIconPng),
+  iosIcon: fromRepoRoot(BRAND_ASSET_PATHS.nightlyIconComposerProject),
+  splashIcon: fromRepoRoot(BRAND_ASSET_PATHS.nightlyIosIconPng),
+  androidAdaptiveForeground: fromRepoRoot(BRAND_ASSET_PATHS.nightlyLinuxIconPng),
+  androidAdaptiveBackgroundColor: "#111533",
+  androidMonochromeIcon: "./assets/android-icon-mark.png",
+  androidNotificationIcon: "./assets/android-notification-icon.png",
+  androidNotificationColor: "#7565C7",
+} as const;
+
 const RELEASE_ASSETS = {
-  appIcon: "./assets/splash-icon-prod.png",
-  iosIcon: "./assets/icon-composer-prod.icon",
-  splashIcon: "./assets/splash-icon-prod.png",
+  appIcon: fromRepoRoot(BRAND_ASSET_PATHS.productionIosIconPng),
+  iosIcon: fromRepoRoot(BRAND_ASSET_PATHS.productionIconComposerProject),
+  splashIcon: fromRepoRoot(BRAND_ASSET_PATHS.productionIosIconPng),
   androidAdaptiveForeground: "./assets/android-icon-mark.png",
   androidAdaptiveBackgroundColor: "#000000",
   androidMonochromeIcon: "./assets/android-icon-mark.png",
@@ -62,7 +76,7 @@ const VARIANT_CONFIG = {
     iosBundleIdentifier: "com.t3tools.t3code.preview",
     androidPackage: "com.t3tools.t3code.preview",
     relyingParty: "clerk.t3.codes",
-    assets: RELEASE_ASSETS,
+    assets: PREVIEW_ASSETS,
   },
   production: {
     appName: "T3 Code",
diff --git a/apps/mobile/assets/android-icon-dev-foreground.png b/apps/mobile/assets/android-icon-dev-foreground.png
deleted file mode 100644
index b33d7978d720..000000000000
Binary files a/apps/mobile/assets/android-icon-dev-foreground.png and /dev/null differ
diff --git a/apps/mobile/assets/icon-composer-dev.icon/Assets/Texturelabs_Paper_381XL.jpg b/apps/mobile/assets/icon-composer-dev.icon/Assets/Texturelabs_Paper_381XL.jpg
deleted file mode 100644
index d98c41a4e3e8..000000000000
Binary files a/apps/mobile/assets/icon-composer-dev.icon/Assets/Texturelabs_Paper_381XL.jpg and /dev/null differ
diff --git a/apps/mobile/assets/icon-composer-dev.icon/Assets/gpt-image-1.5-jd70szmrd03p36z4zv48ycsbax81egvr.png b/apps/mobile/assets/icon-composer-dev.icon/Assets/gpt-image-1.5-jd70szmrd03p36z4zv48ycsbax81egvr.png
deleted file mode 100644
index de5a82d8c49e..000000000000
Binary files a/apps/mobile/assets/icon-composer-dev.icon/Assets/gpt-image-1.5-jd70szmrd03p36z4zv48ycsbax81egvr.png and /dev/null differ
diff --git a/apps/mobile/assets/icon-composer-prod.icon/Assets/T3.svg b/apps/mobile/assets/icon-composer-prod.icon/Assets/T3.svg
deleted file mode 100644
index b12706fdfc23..000000000000
--- a/apps/mobile/assets/icon-composer-prod.icon/Assets/T3.svg
+++ /dev/null
@@ -1,3 +0,0 @@
-<svg width="77" height="47" viewBox="0 0 77 47" fill="none" xmlns="http://www.w3.org/2000/svg">
-<path d="M14.56 45.5V8.58H1.69082e-06V-3.09944e-06H39.65V8.58H25.09V45.5H14.56ZM57.8454 46.28C54.6821 46.28 51.5404 45.8683 48.4204 45.045C45.3004 44.1783 42.6571 42.965 40.4904 41.405L44.5854 33.345C46.3188 34.6017 48.3338 35.5983 50.6304 36.335C52.9271 37.0717 55.2454 37.44 57.5854 37.44C60.2288 37.44 62.3088 36.92 63.8254 35.88C65.3421 34.84 66.1004 33.41 66.1004 31.59C66.1004 29.8567 65.4288 28.4917 64.0854 27.495C62.7421 26.4983 60.5754 26 57.5854 26H52.7754V19.045L65.4504 4.68L66.6204 8.45H42.7654V-3.09944e-06H74.6154V6.825L62.0054 21.19L56.6754 18.135H59.7304C65.3204 18.135 69.5454 19.3917 72.4054 21.905C75.2654 24.4183 76.6954 27.6467 76.6954 31.59C76.6954 34.1467 76.0238 36.5517 74.6804 38.805C73.3371 41.015 71.2788 42.8133 68.5054 44.2C65.7321 45.5867 62.1788 46.28 57.8454 46.28Z" fill="white"/>
-</svg>
diff --git a/apps/mobile/assets/splash-icon-dev.png b/apps/mobile/assets/splash-icon-dev.png
deleted file mode 100644
index b33d6f337b0b..000000000000
Binary files a/apps/mobile/assets/splash-icon-dev.png and /dev/null differ
diff --git a/apps/mobile/assets/splash-icon-prod.png b/apps/mobile/assets/splash-icon-prod.png
deleted file mode 100644
index 2ff311ce786f..000000000000
Binary files a/apps/mobile/assets/splash-icon-prod.png and /dev/null differ
diff --git a/apps/mobile/src/components/BrandMark.tsx b/apps/mobile/src/components/BrandMark.tsx
index 4d1ac01b1ff4..c8f1d4385517 100644
--- a/apps/mobile/src/components/BrandMark.tsx
+++ b/apps/mobile/src/components/BrandMark.tsx
@@ -1,13 +1,23 @@
-import { Image, View } from "react-native";
+import Constants from "expo-constants";
+import { Image } from "expo-image";
+import { View } from "react-native";
 
 import { AppText as Text } from "./AppText";
 
-const BRAND_MARK_SOURCE = require("../../../../assets/dev/blueprint-ios-1024.png");
+const appVariant = Constants.expoConfig?.extra?.appVariant;
+const BRAND_MARK_SOURCE =
+  appVariant === "development"
+    ? require("../../../../assets/dev/blueprint-ios-1024.png")
+    : appVariant === "preview"
+      ? require("../../../../assets/nightly/nightly-ios-1024.png")
+      : require("../../../../assets/prod/black-ios-1024.png");
+const DEFAULT_STAGE_LABEL =
+  appVariant === "development" ? "Dev" : appVariant === "preview" ? "Preview" : "Alpha";
 
 export function BrandMark(props: { readonly compact?: boolean; readonly stageLabel?: string }) {
   const compact = props.compact ?? false;
   const iconSize = compact ? 32 : 44;
-  const stageLabel = props.stageLabel ?? "Alpha";
+  const stageLabel = props.stageLabel ?? DEFAULT_STAGE_LABEL;
 
   return (
     <View className="flex-row items-center gap-3">
diff --git a/apps/server/src/provider/CodexDeveloperInstructions.ts b/apps/server/src/provider/CodexDeveloperInstructions.ts
index b46a4ce1ba3c..35ffd1a4756f 100644
--- a/apps/server/src/provider/CodexDeveloperInstructions.ts
+++ b/apps/server/src/provider/CodexDeveloperInstructions.ts
@@ -1,3 +1,5 @@
+import type { ProviderInteractionMode } from "@t3tools/contracts";
+
 const T3_CODE_BROWSER_TOOL_INSTRUCTIONS = `
 
 ## T3 Code collaborative browser
@@ -145,3 +147,26 @@ The \`request_user_input\` tool is unavailable in Default mode. If you call it w
 In Default mode, strongly prefer making reasonable assumptions and executing the user's request rather than stopping to ask questions. If you absolutely must ask a question because the answer cannot be discovered from local context and a reasonable assumption would be risky, ask the user directly with a concise plain-text question. Never write a multiple choice question as a textual assistant message.
 ${T3_CODE_BROWSER_TOOL_INSTRUCTIONS}
 </collaboration_mode>`;
+
+export interface CodexRuntimeInfo {
+  readonly model: string;
+  readonly reasoningEffort: string;
+}
+
+// Values come from trusted config, but keep the block single-line regardless.
+function toSingleLine(value: string): string {
+  return value.replaceAll(/\s+/g, " ").trim();
+}
+
+export function buildCodexDeveloperInstructions(
+  interactionMode: ProviderInteractionMode,
+  runtime: CodexRuntimeInfo,
+): string {
+  const base =
+    interactionMode === "plan"
+      ? CODEX_PLAN_MODE_DEVELOPER_INSTRUCTIONS
+      : CODEX_DEFAULT_MODE_DEVELOPER_INSTRUCTIONS;
+  return `${base}
+
+<runtime_info>In case you're asked: you are running in T3 Code through the Codex harness, as ${toSingleLine(runtime.model)} with ${toSingleLine(runtime.reasoningEffort)} reasoning effort. No need to mention this otherwise.</runtime_info>`;
+}
diff --git a/apps/server/src/provider/Drivers/ClaudeDriver.ts b/apps/server/src/provider/Drivers/ClaudeDriver.ts
index f2b04b3a2820..ee9cddf949cf 100644
--- a/apps/server/src/provider/Drivers/ClaudeDriver.ts
+++ b/apps/server/src/provider/Drivers/ClaudeDriver.ts
@@ -119,6 +119,7 @@ export const ClaudeDriver: ProviderDriver<ClaudeSettings, ClaudeDriverEnv> = {
     Effect.gen(function* () {
       const spawner = yield* ChildProcessSpawner.ChildProcessSpawner;
       const path = yield* Path.Path;
+      const { cwd } = yield* ServerConfig;
       const httpClient = yield* HttpClient.HttpClient;
       const serverSettings = yield* ServerSettingsService;
       const eventLoggers = yield* ProviderEventLoggers;
@@ -154,11 +155,11 @@ export const ClaudeDriver: ProviderDriver<ClaudeSettings, ClaudeDriverEnv> = {
         capacity: 1,
         timeToLive: CAPABILITIES_PROBE_TTL,
         lookup: () =>
-          probeClaudeCapabilities(effectiveConfig, processEnv).pipe(
+          probeClaudeCapabilities(effectiveConfig, processEnv, cwd).pipe(
             Effect.provideService(Path.Path, path),
           ),
       });
-      const capabilitiesCacheKey = yield* makeClaudeCapabilitiesCacheKey(effectiveConfig);
+      const capabilitiesCacheKey = yield* makeClaudeCapabilitiesCacheKey(effectiveConfig, cwd);
 
       const checkProvider = checkClaudeProviderStatus(
         effectiveConfig,
diff --git a/apps/server/src/provider/Drivers/ClaudeHome.test.ts b/apps/server/src/provider/Drivers/ClaudeHome.test.ts
index 1839e850af1b..d30666b736ea 100644
--- a/apps/server/src/provider/Drivers/ClaudeHome.test.ts
+++ b/apps/server/src/provider/Drivers/ClaudeHome.test.ts
@@ -41,11 +41,20 @@ it.layer(NodeServices.layer)("ClaudeHome", (it) => {
           `claude:home:${configDir}`,
         );
         expect(yield* makeClaudeCapabilitiesCacheKey({ binaryPath: "claude", homePath })).toBe(
-          `claude\0${configDir}`,
+          `claude\0${configDir}\0`,
         );
       }),
     );
 
+    it.effect("separates capability probes by cwd", () =>
+      Effect.gen(function* () {
+        const config = { binaryPath: "claude", homePath: "" };
+        const first = yield* makeClaudeCapabilitiesCacheKey(config, "/repo-a");
+        const second = yield* makeClaudeCapabilitiesCacheKey(config, "/repo-b");
+        expect(first).not.toBe(second);
+      }),
+    );
+
     it.effect("treats paths that already end with .claude as the config dir", () =>
       Effect.gen(function* () {
         const path = yield* Path.Path;
diff --git a/apps/server/src/provider/Drivers/ClaudeHome.ts b/apps/server/src/provider/Drivers/ClaudeHome.ts
index b42c26157ce0..d839d0b4a629 100644
--- a/apps/server/src/provider/Drivers/ClaudeHome.ts
+++ b/apps/server/src/provider/Drivers/ClaudeHome.ts
@@ -72,8 +72,9 @@ export const makeClaudeContinuationGroupKey = Effect.fn("makeClaudeContinuationG
 export const makeClaudeCapabilitiesCacheKey = Effect.fn("makeClaudeCapabilitiesCacheKey")(
   function* (
     config: Pick<ClaudeSettings, "binaryPath" | "homePath">,
+    cwd?: string,
   ): Effect.fn.Return<string, never, Path.Path> {
     const configDir = yield* resolveClaudeConfigDir(config);
-    return `${config.binaryPath}\0${configDir}`;
+    return `${config.binaryPath}\0${configDir}\0${cwd ?? ""}`;
   },
 );
diff --git a/apps/server/src/provider/Drivers/GrokDriver.ts b/apps/server/src/provider/Drivers/GrokDriver.ts
index d855d1a45151..4eb32c20c472 100644
--- a/apps/server/src/provider/Drivers/GrokDriver.ts
+++ b/apps/server/src/provider/Drivers/GrokDriver.ts
@@ -84,6 +84,7 @@ export const GrokDriver: ProviderDriver<GrokSettings, GrokDriverEnv> = {
   defaultConfig: (): GrokSettings => decodeGrokSettings({}),
   create: ({ instanceId, displayName, accentColor, environment, enabled, config }) =>
     Effect.gen(function* () {
+      const crypto = yield* Crypto.Crypto;
       const spawner = yield* ChildProcessSpawner.ChildProcessSpawner;
       const httpClient = yield* HttpClient.HttpClient;
       const serverSettings = yield* ServerSettingsService;
@@ -114,6 +115,7 @@ export const GrokDriver: ProviderDriver<GrokSettings, GrokDriverEnv> = {
 
       const checkProvider = checkGrokProviderStatus(effectiveConfig, processEnv).pipe(
         Effect.map(stampIdentity),
+        Effect.provideService(Crypto.Crypto, crypto),
         Effect.provideService(ChildProcessSpawner.ChildProcessSpawner, spawner),
       );
 
diff --git a/apps/server/src/provider/Layers/ClaudeProvider.ts b/apps/server/src/provider/Layers/ClaudeProvider.ts
index 8a98f38816e8..2e35731c7671 100644
--- a/apps/server/src/provider/Layers/ClaudeProvider.ts
+++ b/apps/server/src/provider/Layers/ClaudeProvider.ts
@@ -644,6 +644,7 @@ function waitForAbortSignal(signal: AbortSignal): Promise<void> {
 const probeClaudeCapabilities = (
   claudeSettings: ClaudeSettings,
   environment?: NodeJS.ProcessEnv,
+  cwd?: string,
 ) => {
   const abort = new AbortController();
   return Effect.gen(function* () {
@@ -663,6 +664,7 @@ const probeClaudeCapabilities = (
           settingSources: ["user", "project", "local"],
           allowedTools: [],
           env: claudeEnvironment,
+          ...(cwd ? { cwd } : {}),
           stderr: () => {},
         },
       });
diff --git a/apps/server/src/provider/Layers/CodexSessionRuntime.test.ts b/apps/server/src/provider/Layers/CodexSessionRuntime.test.ts
index 8aeacd870cc4..1527072dae7a 100644
--- a/apps/server/src/provider/Layers/CodexSessionRuntime.test.ts
+++ b/apps/server/src/provider/Layers/CodexSessionRuntime.test.ts
@@ -4,11 +4,12 @@ import { it } from "@effect/vitest";
 import * as Effect from "effect/Effect";
 import * as Schema from "effect/Schema";
 import { describe } from "vite-plus/test";
-import { ThreadId } from "@t3tools/contracts";
+import { DEFAULT_MODEL, ThreadId } from "@t3tools/contracts";
 import * as CodexErrors from "effect-codex-app-server/errors";
 import * as CodexRpc from "effect-codex-app-server/rpc";
 
 import {
+  buildCodexDeveloperInstructions,
   CODEX_DEFAULT_MODE_DEVELOPER_INSTRUCTIONS,
   CODEX_PLAN_MODE_DEVELOPER_INSTRUCTIONS,
 } from "../CodexDeveloperInstructions.ts";
@@ -118,7 +119,10 @@ describe("buildTurnStartParams", () => {
         settings: {
           model: "gpt-5.3-codex",
           reasoning_effort: "medium",
-          developer_instructions: CODEX_PLAN_MODE_DEVELOPER_INSTRUCTIONS,
+          developer_instructions: buildCodexDeveloperInstructions("plan", {
+            model: "gpt-5.3-codex",
+            reasoningEffort: "medium",
+          }),
         },
       },
     });
@@ -163,12 +167,31 @@ describe("buildTurnStartParams", () => {
         settings: {
           model: "gpt-5.3-codex",
           reasoning_effort: "medium",
-          developer_instructions: CODEX_DEFAULT_MODE_DEVELOPER_INSTRUCTIONS,
+          developer_instructions: buildCodexDeveloperInstructions("default", {
+            model: "gpt-5.3-codex",
+            reasoningEffort: "medium",
+          }),
         },
       },
     });
   });
 
+  it("reports the same fallback model and effort in settings and instructions", () => {
+    const params = Effect.runSync(
+      buildTurnStartParams({
+        threadId: "provider-thread-1",
+        runtimeMode: "full-access",
+        prompt: "Go",
+        interactionMode: "default",
+      }),
+    );
+
+    const settings = params.collaborationMode?.settings;
+    NodeAssert.equal(settings?.model, DEFAULT_MODEL);
+    NodeAssert.equal(settings?.reasoning_effort, "medium");
+    NodeAssert.ok(settings?.developer_instructions?.includes(`as ${DEFAULT_MODEL} with medium`));
+  });
+
   it("omits collaboration mode when interaction mode is absent", () => {
     const params = Effect.runSync(
       buildTurnStartParams({
@@ -194,6 +217,53 @@ describe("buildTurnStartParams", () => {
   });
 });
 
+describe("buildCodexDeveloperInstructions", () => {
+  it("appends runtime info after the mode instructions", () => {
+    const instructions = buildCodexDeveloperInstructions("default", {
+      model: "gpt-5.3-codex",
+      reasoningEffort: "high",
+    });
+
+    NodeAssert.ok(instructions.startsWith(CODEX_DEFAULT_MODE_DEVELOPER_INSTRUCTIONS));
+    NodeAssert.match(instructions, /T3 Code/);
+    NodeAssert.match(instructions, /Codex harness/);
+    NodeAssert.match(instructions, /as gpt-5\.3-codex with high reasoning effort/);
+  });
+
+  it("includes runtime info alongside plan mode instructions", () => {
+    const instructions = buildCodexDeveloperInstructions("plan", {
+      model: "gpt-5.3-codex",
+      reasoningEffort: "medium",
+    });
+
+    NodeAssert.ok(instructions.startsWith(CODEX_PLAN_MODE_DEVELOPER_INSTRUCTIONS));
+    NodeAssert.match(instructions, /as gpt-5\.3-codex with medium reasoning effort/);
+  });
+
+  it("varies with the model and effort of each turn", () => {
+    const first = buildCodexDeveloperInstructions("default", {
+      model: "gpt-5.3-codex",
+      reasoningEffort: "medium",
+    });
+    const second = buildCodexDeveloperInstructions("default", {
+      model: "gpt-5.4",
+      reasoningEffort: "high",
+    });
+
+    NodeAssert.notEqual(first, second);
+  });
+
+  it("flattens multiline metadata into single-line runtime info", () => {
+    const instructions = buildCodexDeveloperInstructions("default", {
+      model: "gpt\n5.3\ncodex",
+      reasoningEffort: " high\neffort ",
+    });
+
+    NodeAssert.match(instructions, /as gpt 5\.3 codex with high effort reasoning effort/);
+    NodeAssert.doesNotMatch(instructions, /<runtime_info>[^<]*\n/);
+  });
+});
+
 describe("T3 browser developer instructions", () => {
   it("prefers the product-native preview tools in both collaboration modes", () => {
     for (const instructions of [
diff --git a/apps/server/src/provider/Layers/CodexSessionRuntime.ts b/apps/server/src/provider/Layers/CodexSessionRuntime.ts
index 5825dd6ea33b..4a320fa78a27 100644
--- a/apps/server/src/provider/Layers/CodexSessionRuntime.ts
+++ b/apps/server/src/provider/Layers/CodexSessionRuntime.ts
@@ -37,10 +37,7 @@ import * as EffectCodexSchema from "effect-codex-app-server/schema";
 
 import { buildCodexInitializeParams } from "./CodexProvider.ts";
 import { expandHomePath } from "../../pathExpansion.ts";
-import {
-  CODEX_DEFAULT_MODE_DEVELOPER_INSTRUCTIONS,
-  CODEX_PLAN_MODE_DEVELOPER_INSTRUCTIONS,
-} from "../CodexDeveloperInstructions.ts";
+import { buildCodexDeveloperInstructions } from "../CodexDeveloperInstructions.ts";
 const decodeV2TurnStartResponse = Schema.decodeUnknownEffect(EffectCodexSchema.V2TurnStartResponse);
 
 const PROVIDER = ProviderDriverKind.make("codex");
@@ -333,15 +330,16 @@ function buildCodexCollaborationMode(input: {
     return undefined;
   }
   const model = normalizeCodexModelSlug(input.model) ?? DEFAULT_MODEL;
+  const reasoningEffort = input.effort ?? "medium";
   return {
     mode: input.interactionMode,
     settings: {
       model,
-      reasoning_effort: input.effort ?? "medium",
-      developer_instructions:
-        input.interactionMode === "plan"
-          ? CODEX_PLAN_MODE_DEVELOPER_INSTRUCTIONS
-          : CODEX_DEFAULT_MODE_DEVELOPER_INSTRUCTIONS,
+      reasoning_effort: reasoningEffort,
+      developer_instructions: buildCodexDeveloperInstructions(input.interactionMode, {
+        model,
+        reasoningEffort,
+      }),
     },
   };
 }
diff --git a/apps/server/src/provider/Layers/GrokAdapter.ts b/apps/server/src/provider/Layers/GrokAdapter.ts
index c22b21801835..d8c288a8292f 100644
--- a/apps/server/src/provider/Layers/GrokAdapter.ts
+++ b/apps/server/src/provider/Layers/GrokAdapter.ts
@@ -596,6 +596,7 @@ export function makeGrokAdapter(grokSettings: GrokSettings, options?: GrokAdapte
               : {}),
             ...acpNativeLoggers,
           }).pipe(
+            Effect.provideService(Crypto.Crypto, crypto),
             Effect.provideService(Scope.Scope, sessionScope),
             Effect.mapError(
               (cause) =>
diff --git a/apps/server/src/provider/Layers/GrokProvider.ts b/apps/server/src/provider/Layers/GrokProvider.ts
index cf5d5ad9c8d8..33f61ad97f6d 100644
--- a/apps/server/src/provider/Layers/GrokProvider.ts
+++ b/apps/server/src/provider/Layers/GrokProvider.ts
@@ -7,6 +7,7 @@ import {
 } from "@t3tools/contracts";
 import type * as EffectAcpSchema from "effect-acp/schema";
 import { causeErrorTag } from "@t3tools/shared/observability";
+import * as Crypto from "effect/Crypto";
 import * as DateTime from "effect/DateTime";
 import * as Effect from "effect/Effect";
 import * as Exit from "effect/Exit";
@@ -167,7 +168,11 @@ const runGrokVersionCommand = (
 export const checkGrokProviderStatus = Effect.fn("checkGrokProviderStatus")(function* (
   grokSettings: GrokSettings,
   environment: NodeJS.ProcessEnv = process.env,
-): Effect.fn.Return<ServerProviderDraft, never, ChildProcessSpawner.ChildProcessSpawner> {
+): Effect.fn.Return<
+  ServerProviderDraft,
+  never,
+  ChildProcessSpawner.ChildProcessSpawner | Crypto.Crypto
+> {
   const checkedAt = DateTime.formatIso(yield* DateTime.now);
   const fallbackModels = grokModelsFromSettings(grokSettings.customModels);
 
diff --git a/apps/server/src/provider/Layers/ProviderInstanceRegistryLive.test.ts b/apps/server/src/provider/Layers/ProviderInstanceRegistryLive.test.ts
index f1a51616c480..547e7bd92c57 100644
--- a/apps/server/src/provider/Layers/ProviderInstanceRegistryLive.test.ts
+++ b/apps/server/src/provider/Layers/ProviderInstanceRegistryLive.test.ts
@@ -76,7 +76,7 @@ const makeClaudeConfig = (overrides: Partial<ClaudeSettings>): ClaudeSettings =>
 
 const makeCursorConfig = (overrides: Partial<CursorSettings>): CursorSettings => ({
   enabled: false,
-  binaryPath: "agent",
+  binaryPath: "cursor-agent",
   apiEndpoint: "",
   customModels: [],
   ...overrides,
diff --git a/apps/server/src/provider/Layers/ProviderRegistry.test.ts b/apps/server/src/provider/Layers/ProviderRegistry.test.ts
index dc88eb67e79b..886eff5ef1b8 100644
--- a/apps/server/src/provider/Layers/ProviderRegistry.test.ts
+++ b/apps/server/src/provider/Layers/ProviderRegistry.test.ts
@@ -1411,7 +1411,7 @@ it.layer(Layer.mergeAll(NodeServices.layer, ServerSettingsModule.layerTest(), Te
               Layer.provideMerge(OpenCodeRuntime.OpenCodeRuntimeLive),
               Layer.provideMerge(
                 mockCommandSpawnerLayer((command, args) => {
-                  if (command === "agent") {
+                  if (command === "cursor-agent") {
                     cursorSpawned = true;
                   }
                   const joined = args.join(" ");
diff --git a/apps/server/src/provider/acp/AcpJsonRpcConnection.test.ts b/apps/server/src/provider/acp/AcpJsonRpcConnection.test.ts
index 4e9700dab7d6..b1ef0d3e5953 100644
--- a/apps/server/src/provider/acp/AcpJsonRpcConnection.test.ts
+++ b/apps/server/src/provider/acp/AcpJsonRpcConnection.test.ts
@@ -116,6 +116,43 @@ describe("AcpSessionRuntime", () => {
     ),
   );
 
+  it.effect("keeps assistant item IDs unique when a provider session restarts", () => {
+    const collectFirstAssistantItemId = Effect.gen(function* () {
+      const runtime = yield* AcpSessionRuntime.AcpSessionRuntime;
+      const started = yield* runtime.start();
+      expect(started.sessionId).toBe("mock-session-1");
+
+      yield* runtime.prompt({
+        prompt: [{ type: "text", text: "hi" }],
+      });
+
+      const events = Array.from(yield* Stream.runCollect(Stream.take(runtime.getEvents(), 4)));
+      const assistantStart = events.find((event) => event._tag === "AssistantItemStarted");
+      expect(assistantStart?._tag).toBe("AssistantItemStarted");
+      return assistantStart?._tag === "AssistantItemStarted" ? assistantStart.itemId : "";
+    }).pipe(
+      Effect.provide(
+        AcpSessionRuntime.layer({
+          spawn: {
+            command: mockAgentCommand,
+            args: mockAgentArgs,
+          },
+          cwd: process.cwd(),
+          clientInfo: { name: "t3-test", version: "0.0.0" },
+          authMethodId: "test",
+        }),
+      ),
+      Effect.scoped,
+    );
+
+    return Effect.gen(function* () {
+      const beforeRestart = yield* collectFirstAssistantItemId;
+      const afterRestart = yield* collectFirstAssistantItemId;
+
+      expect(afterRestart).not.toBe(beforeRestart);
+    }).pipe(Effect.provide(NodeServices.layer));
+  });
+
   it.effect("drops session updates emitted for a child ACP session", () =>
     Effect.gen(function* () {
       const runtime = yield* AcpSessionRuntime.AcpSessionRuntime;
diff --git a/apps/server/src/provider/acp/AcpSessionRuntime.ts b/apps/server/src/provider/acp/AcpSessionRuntime.ts
index bd10e46b0cf6..82cad3921a49 100644
--- a/apps/server/src/provider/acp/AcpSessionRuntime.ts
+++ b/apps/server/src/provider/acp/AcpSessionRuntime.ts
@@ -1,6 +1,7 @@
 import * as Cause from "effect/Cause";
 import * as Clock from "effect/Clock";
 import * as Context from "effect/Context";
+import * as Crypto from "effect/Crypto";
 import * as Deferred from "effect/Deferred";
 import * as Duration from "effect/Duration";
 import * as Effect from "effect/Effect";
@@ -270,14 +271,24 @@ export const make = (
 ): Effect.Effect<
   AcpSessionRuntime["Service"],
   EffectAcpErrors.AcpError,
-  ChildProcessSpawner.ChildProcessSpawner | Scope.Scope
+  ChildProcessSpawner.ChildProcessSpawner | Crypto.Crypto | Scope.Scope
 > =>
   Effect.gen(function* () {
+    const crypto = yield* Crypto.Crypto;
     const spawner = yield* ChildProcessSpawner.ChildProcessSpawner;
     const runtimeScope = yield* Scope.Scope;
     const eventQueue = yield* Queue.unbounded<AcpSessionRuntimeEvent>();
     const modeStateRef = yield* Ref.make<AcpSessionModeState | undefined>(undefined);
     const toolCallsRef = yield* Ref.make(new Map<string, AcpToolCallState>());
+    const assistantItemRuntimeId = yield* crypto.randomUUIDv4.pipe(
+      Effect.mapError(
+        (cause) =>
+          new EffectAcpErrors.AcpTransportError({
+            detail: "Failed to generate an ACP assistant item runtime identifier.",
+            cause,
+          }),
+      ),
+    );
     const assistantSegmentRef = yield* Ref.make<AcpAssistantSegmentState>({ nextSegmentIndex: 0 });
     const configOptionsRef = yield* Ref.make(sessionConfigOptionsFromSetup(undefined));
     const startStateRef = yield* Ref.make<AcpStartState>({ _tag: "NotStarted" });
@@ -393,6 +404,7 @@ export const make = (
           modeStateRef,
           toolCallsRef,
           assistantSegmentRef,
+          assistantItemRuntimeId,
           params: notification,
         });
       }),
@@ -817,7 +829,7 @@ export const layer = (
 ): Layer.Layer<
   AcpSessionRuntime,
   EffectAcpErrors.AcpError,
-  ChildProcessSpawner.ChildProcessSpawner
+  ChildProcessSpawner.ChildProcessSpawner | Crypto.Crypto
 > => Layer.effect(AcpSessionRuntime, make(options));
 
 function sessionConfigOptionsFromSetup(
@@ -849,12 +861,14 @@ const handleSessionUpdate = ({
   modeStateRef,
   toolCallsRef,
   assistantSegmentRef,
+  assistantItemRuntimeId,
   params,
 }: {
   readonly queue: Queue.Queue<AcpSessionRuntimeEvent>;
   readonly modeStateRef: Ref.Ref<AcpSessionModeState | undefined>;
   readonly toolCallsRef: Ref.Ref<Map<string, AcpToolCallState>>;
   readonly assistantSegmentRef: Ref.Ref<AcpAssistantSegmentState>;
+  readonly assistantItemRuntimeId: string;
   readonly params: EffectAcpSchema.SessionNotification;
 }): Effect.Effect<void> =>
   Effect.gen(function* () {
@@ -902,6 +916,7 @@ const handleSessionUpdate = ({
           queue,
           assistantSegmentRef,
           sessionId: params.sessionId,
+          assistantItemRuntimeId,
         });
         yield* Queue.offer(queue, {
           ...event,
@@ -939,17 +954,19 @@ function shouldEmitToolCallUpdate(
   return previous === undefined || previous.title !== next.title || previous.detail !== next.detail;
 }
 
-const assistantItemId = (sessionId: string, segmentIndex: number) =>
-  `assistant:${sessionId}:segment:${segmentIndex}`;
+const assistantItemId = (sessionId: string, runtimeId: string, segmentIndex: number) =>
+  `assistant:${sessionId}:runtime:${runtimeId}:segment:${segmentIndex}`;
 
 const ensureActiveAssistantSegment = ({
   queue,
   assistantSegmentRef,
   sessionId,
+  assistantItemRuntimeId,
 }: {
   readonly queue: Queue.Queue<AcpSessionRuntimeEvent>;
   readonly assistantSegmentRef: Ref.Ref<AcpAssistantSegmentState>;
   readonly sessionId: string;
+  readonly assistantItemRuntimeId: string;
 }) =>
   Ref.modify<AcpAssistantSegmentState, EnsureActiveAssistantSegmentResult>(
     assistantSegmentRef,
@@ -957,7 +974,7 @@ const ensureActiveAssistantSegment = ({
       if (current.activeItemId) {
         return [{ itemId: current.activeItemId }, current] as const;
       }
-      const itemId = assistantItemId(sessionId, current.nextSegmentIndex);
+      const itemId = assistantItemId(sessionId, assistantItemRuntimeId, current.nextSegmentIndex);
       return [
         {
           itemId,
diff --git a/apps/server/src/provider/acp/GrokAcpSupport.ts b/apps/server/src/provider/acp/GrokAcpSupport.ts
index 3e6d63a53935..c928b3ed80e0 100644
--- a/apps/server/src/provider/acp/GrokAcpSupport.ts
+++ b/apps/server/src/provider/acp/GrokAcpSupport.ts
@@ -1,4 +1,5 @@
 import { type GrokSettings, ProviderDriverKind } from "@t3tools/contracts";
+import * as Crypto from "effect/Crypto";
 import * as Effect from "effect/Effect";
 import * as Layer from "effect/Layer";
 import * as Scope from "effect/Scope";
@@ -55,7 +56,7 @@ export const makeGrokAcpRuntime = (
 ): Effect.Effect<
   AcpSessionRuntime.AcpSessionRuntime["Service"],
   EffectAcpErrors.AcpError,
-  Scope.Scope
+  Crypto.Crypto | Scope.Scope
 > =>
   Effect.gen(function* () {
     const acpContext = yield* Layer.build(
diff --git a/apps/server/src/provider/providerMaintenanceRunner.test.ts b/apps/server/src/provider/providerMaintenanceRunner.test.ts
index f33a9bbce426..641c9b52e56c 100644
--- a/apps/server/src/provider/providerMaintenanceRunner.test.ts
+++ b/apps/server/src/provider/providerMaintenanceRunner.test.ts
@@ -48,7 +48,7 @@ function lifecycleFor(provider: ProviderDriverKind): ProviderMaintenanceCapabili
     return makeProviderMaintenanceCapabilities({
       provider,
       packageName: null,
-      updateExecutable: "agent",
+      updateExecutable: "cursor-agent",
       updateArgs: ["update"],
       updateLockKey: "cursor-agent",
     });
@@ -226,7 +226,7 @@ describe("providerMaintenanceRunner", () => {
       const result = yield* updater.updateProvider(CURSOR_DRIVER);
       assert.deepStrictEqual(calls, [
         {
-          command: "agent",
+          command: "cursor-agent",
           args: ["update"],
         },
       ]);
diff --git a/apps/server/src/textGeneration/GrokTextGeneration.ts b/apps/server/src/textGeneration/GrokTextGeneration.ts
index 1bb582163056..fd367acdf4c4 100644
--- a/apps/server/src/textGeneration/GrokTextGeneration.ts
+++ b/apps/server/src/textGeneration/GrokTextGeneration.ts
@@ -1,3 +1,4 @@
+import * as Crypto from "effect/Crypto";
 import * as Effect from "effect/Effect";
 import * as Option from "effect/Option";
 import * as Ref from "effect/Ref";
@@ -37,6 +38,7 @@ export const makeGrokTextGeneration = Effect.fn("makeGrokTextGeneration")(functi
   grokSettings: GrokSettings,
   environment: NodeJS.ProcessEnv = process.env,
 ) {
+  const crypto = yield* Crypto.Crypto;
   const commandSpawner = yield* ChildProcessSpawner.ChildProcessSpawner;
 
   const runGrokJson = <S extends Schema.Top>({
@@ -65,7 +67,7 @@ export const makeGrokTextGeneration = Effect.fn("makeGrokTextGeneration")(functi
         childProcessSpawner: commandSpawner,
         cwd,
         clientInfo: { name: "t3-code-git-text", version: "0.0.0" },
-      });
+      }).pipe(Effect.provideService(Crypto.Crypto, crypto));
 
       yield* runtime.handleSessionUpdate((notification) => {
         const update = notification.update;
diff --git a/apps/web/src/components/AppSidebarLayout.tsx b/apps/web/src/components/AppSidebarLayout.tsx
index 455cc9199f64..aefa9ab9f418 100644
--- a/apps/web/src/components/AppSidebarLayout.tsx
+++ b/apps/web/src/components/AppSidebarLayout.tsx
@@ -1,6 +1,6 @@
 import { useAtomValue } from "@effect/atom-react";
-import { useEffect, useState, type CSSProperties, type ReactNode } from "react";
-import { useNavigate } from "@tanstack/react-router";
+import { useEffect, useRef, useState, type CSSProperties, type ReactNode } from "react";
+import { useLocation, useNavigate } from "@tanstack/react-router";
 
 import { isElectron } from "../env";
 import { resolveShortcutCommand, shortcutLabelForCommand } from "../keybindings";
@@ -55,6 +55,9 @@ function SidebarControl() {
 
 export function AppSidebarLayout({ children }: { children: ReactNode }) {
   const navigate = useNavigate();
+  const pathname = useLocation({ select: (location) => location.pathname });
+  const pathnameRef = useRef(pathname);
+  pathnameRef.current = pathname;
   const isMacosDesktop = isElectron && isMacPlatform(navigator.platform);
   const [isWindowFullscreen, setIsWindowFullscreen] = useState(() => {
     const getWindowFullscreenState = window.desktopBridge?.getWindowFullscreenState;
@@ -92,7 +95,10 @@ export function AppSidebarLayout({ children }: { children: ReactNode }) {
 
     const unsubscribe = onMenuAction((action) => {
       if (action === "open-settings") {
-        void navigate({ to: "/settings" });
+        const isSettingsRoute = /^\/settings(\/|$)/.test(pathnameRef.current);
+        if (!isSettingsRoute) {
+          void navigate({ to: "/settings" });
+        }
       }
     });
 
diff --git a/apps/web/src/components/chat/ChatComposer.tsx b/apps/web/src/components/chat/ChatComposer.tsx
index c8baa9183d6b..a59c125a4536 100644
--- a/apps/web/src/components/chat/ChatComposer.tsx
+++ b/apps/web/src/components/chat/ChatComposer.tsx
@@ -41,6 +41,7 @@ import {
   detectComposerTrigger,
   expandCollapsedComposerCursor,
   replaceTextRange,
+  shouldSubmitComposerOnEnter,
 } from "../../composer-logic";
 import { deriveComposerSendState, readFileAsDataUrl } from "../ChatView.logic";
 import {
@@ -1725,7 +1726,10 @@ export const ChatComposer = memo(function ChatComposer(props: ChatComposerProps)
         return true;
       }
     }
-    if (key === "Enter" && !event.shiftKey) {
+    if (
+      key === "Enter" &&
+      shouldSubmitComposerOnEnter({ isMobileViewport, shiftKey: event.shiftKey })
+    ) {
       submitComposer();
       return true;
     }
diff --git a/apps/web/src/components/chat/ComposerPendingUserInputPanel.tsx b/apps/web/src/components/chat/ComposerPendingUserInputPanel.tsx
index d826eca0063a..bd02a91b248e 100644
--- a/apps/web/src/components/chat/ComposerPendingUserInputPanel.tsx
+++ b/apps/web/src/components/chat/ComposerPendingUserInputPanel.tsx
@@ -190,7 +190,7 @@ const ComposerPendingUserInputCard = memo(function ComposerPendingUserInputCard(
               <div className="min-w-0 flex-1 flex flex-col gap-0.5">
                 <span className="text-sm font-medium">{option.label}</span>
                 {option.description && option.description !== option.label ? (
-                  <span className="text-xs text-muted-foreground/50">{option.description}</span>
+                  <span className="text-xs text-muted-foreground">{option.description}</span>
                 ) : null}
               </div>
               {isSelected ? (
diff --git a/apps/web/src/components/desktopUpdate.logic.test.ts b/apps/web/src/components/desktopUpdate.logic.test.ts
index a05bc33a10f2..65083b5b0bfd 100644
--- a/apps/web/src/components/desktopUpdate.logic.test.ts
+++ b/apps/web/src/components/desktopUpdate.logic.test.ts
@@ -24,6 +24,7 @@ const baseState: DesktopUpdateState = {
   runningUnderArm64Translation: false,
   availableVersion: null,
   downloadedVersion: null,
+  releaseNotes: [],
   downloadPercent: null,
   checkedAt: null,
   message: null,
diff --git a/apps/web/src/components/preview/PreviewPanelShell.test.ts b/apps/web/src/components/preview/PreviewPanelShell.test.ts
new file mode 100644
index 000000000000..43bc5ffa7307
--- /dev/null
+++ b/apps/web/src/components/preview/PreviewPanelShell.test.ts
@@ -0,0 +1,18 @@
+import { describe, expect, it } from "vite-plus/test";
+
+import { getPreviewPanelMaxWidth } from "./PreviewPanelShell";
+
+describe("getPreviewPanelMaxWidth", () => {
+  it("allows the panel to use 70% of the available chat+preview row without a pixel ceiling", () => {
+    expect(getPreviewPanelMaxWidth(6_000)).toBe(4_200);
+  });
+
+  it("rounds fractional CSS pixels down", () => {
+    expect(getPreviewPanelMaxWidth(2_001)).toBe(1_400);
+  });
+
+  it("leaves chat room when the available row is narrower than the viewport", () => {
+    // e.g. 6000px viewport minus a 2000px left sidebar → 4000px row
+    expect(getPreviewPanelMaxWidth(4_000)).toBe(2_800);
+  });
+});
diff --git a/apps/web/src/components/preview/PreviewPanelShell.tsx b/apps/web/src/components/preview/PreviewPanelShell.tsx
index 6de828c1e63e..46b02fade011 100644
--- a/apps/web/src/components/preview/PreviewPanelShell.tsx
+++ b/apps/web/src/components/preview/PreviewPanelShell.tsx
@@ -1,4 +1,4 @@
-import { type ReactNode, useEffect, useState } from "react";
+import { type ReactNode, type RefObject, useEffect, useRef, useState } from "react";
 
 import { isElectron } from "~/env";
 import { useResizableWidth } from "~/hooks/useResizableWidth";
@@ -10,12 +10,14 @@ export type PreviewPanelMode = "inline" | "sheet" | "sidebar" | "embedded";
 
 const PREVIEW_PANEL_WIDTH_STORAGE_KEY = "t3code:preview-panel-width";
 const PREVIEW_PANEL_MIN_WIDTH = 360;
-/** Hard ceiling so a wide monitor can't yield a panel that swallows the chat. */
-const PREVIEW_PANEL_MAX_WIDTH_PX = 1400;
-/** Fraction of the viewport allowed; the panel is min(this · vw, MAX_PX). */
+/** Fraction of the available row width allowed, preserving space for chat. */
 const PREVIEW_PANEL_MAX_WIDTH_FRACTION = 0.7;
 const PREVIEW_PANEL_DEFAULT_WIDTH = 540;
 
+export function getPreviewPanelMaxWidth(availableWidth: number): number {
+  return Math.floor(availableWidth * PREVIEW_PANEL_MAX_WIDTH_FRACTION);
+}
+
 /**
  * Shell for the preview panel. In inline mode the panel is user-resizable
  * via a drag handle on the left edge; width persists per browser. In
@@ -28,7 +30,8 @@ export function PreviewPanelShell(props: {
 }) {
   const useDragRegion = isElectron && props.mode !== "sheet" && props.mode !== "embedded";
   const isInline = props.mode === "inline";
-  const maxWidth = useViewportClampedMaxWidth();
+  const panelRef = useRef<HTMLDivElement>(null);
+  const maxWidth = useContainerClampedMaxWidth(panelRef);
   const { width, handlers } = useResizableWidth({
     storageKey: PREVIEW_PANEL_WIDTH_STORAGE_KEY,
     defaultWidth: PREVIEW_PANEL_DEFAULT_WIDTH,
@@ -39,6 +42,7 @@ export function PreviewPanelShell(props: {
 
   return (
     <div
+      ref={panelRef}
       className={cn(
         "relative flex h-full min-h-0 min-w-0 flex-col self-stretch bg-background",
         isInline
@@ -59,28 +63,29 @@ export function PreviewPanelShell(props: {
 }
 
 /**
- * Track viewport width to derive a sensible upper bound for the panel.
- * Resize-aware so dragging the OS window narrower re-clamps the stored
- * width on the next render (the hook's clamp picks this up automatically).
+ * Clamp against the containing flex row (chat + preview), not the full
+ * viewport — left sidebars are outside that row and must not inflate the max.
  */
-function useViewportClampedMaxWidth(): number {
-  const [vw, setVw] = useState(() => (typeof window === "undefined" ? 1280 : window.innerWidth));
+function useContainerClampedMaxWidth(panelRef: RefObject<HTMLDivElement | null>): number {
+  const [availableWidth, setAvailableWidth] = useState(() =>
+    typeof window === "undefined" ? 1280 : window.innerWidth,
+  );
   useEffect(() => {
-    if (typeof window === "undefined") return;
-    let frame = 0;
-    const onResize = () => {
-      // Coalesce rapid resize events into one rAF tick.
-      if (frame !== 0) return;
-      frame = window.requestAnimationFrame(() => {
-        frame = 0;
-        setVw(window.innerWidth);
-      });
-    };
-    window.addEventListener("resize", onResize);
-    return () => {
-      window.removeEventListener("resize", onResize);
-      if (frame !== 0) window.cancelAnimationFrame(frame);
+    const panel = panelRef.current;
+    const container = panel?.parentElement;
+    if (!container || typeof ResizeObserver === "undefined") return;
+
+    const update = (width: number) => {
+      if (width > 0) setAvailableWidth(width);
     };
-  }, []);
-  return Math.min(PREVIEW_PANEL_MAX_WIDTH_PX, Math.floor(vw * PREVIEW_PANEL_MAX_WIDTH_FRACTION));
+    update(container.clientWidth);
+
+    const observer = new ResizeObserver((entries) => {
+      const width = entries[0]?.contentRect.width ?? container.clientWidth;
+      update(width);
+    });
+    observer.observe(container);
+    return () => observer.disconnect();
+  }, [panelRef]);
+  return getPreviewPanelMaxWidth(availableWidth);
 }
diff --git a/apps/web/src/components/preview/PreviewUnreachable.tsx b/apps/web/src/components/preview/PreviewUnreachable.tsx
index c6ada2cb4914..dac80f070b48 100644
--- a/apps/web/src/components/preview/PreviewUnreachable.tsx
+++ b/apps/web/src/components/preview/PreviewUnreachable.tsx
@@ -17,7 +17,7 @@ interface Props {
 export function PreviewUnreachable({ url, code, description, onReload }: Props) {
   const [showDetails, setShowDetails] = useState(false);
   const host = safeHost(url) ?? url;
-  const friendly = describePreviewError(code, description);
+  const friendly = describePreviewError(description);
   const errorLabel = description.length > 0 ? description : `ERR_${Math.abs(code) || "FAILED"}`;
 
   return (
diff --git a/apps/web/src/components/preview/errorCodeMessages.ts b/apps/web/src/components/preview/errorCodeMessages.ts
index 78ee928800b5..76ce7d939230 100644
--- a/apps/web/src/components/preview/errorCodeMessages.ts
+++ b/apps/web/src/components/preview/errorCodeMessages.ts
@@ -2,11 +2,11 @@ import { PREVIEW_ERROR_CODE_MESSAGES } from "./previewConstants";
 
 /**
  * Resolve a friendly description for a Chromium / network error. Falls back
- * to the description string passed in when the code isn't in our table.
+ * to the description string passed in when it isn't in our table.
  */
-export function describePreviewError(code: number, description: string): string {
+export function describePreviewError(description: string): string {
   const friendly = PREVIEW_ERROR_CODE_MESSAGES[description];
   if (friendly) return friendly;
   if (description.length > 0) return description;
-  return `Network error (${code})`;
+  return "Network error";
 }
diff --git a/apps/web/src/components/settings/DiagnosticsSettings.tsx b/apps/web/src/components/settings/DiagnosticsSettings.tsx
index 92d8d3f68272..b1a54feb7188 100644
--- a/apps/web/src/components/settings/DiagnosticsSettings.tsx
+++ b/apps/web/src/components/settings/DiagnosticsSettings.tsx
@@ -23,7 +23,7 @@ import * as Option from "effect/Option";
 
 import { cn } from "../../lib/utils";
 import { resolveAndPersistPreferredEditor } from "../../editorPreferences";
-import { formatRelativeTime } from "../../timestampFormat";
+import { formatRelativeTimeLabel, getRelativeTimeState } from "../../timestampFormat";
 import { useEnvironmentQuery } from "../../state/query";
 import {
   primaryServerAvailableEditorsAtom,
@@ -65,8 +65,7 @@ function formatBytes(value: number): string {
 
 function formatRelative(value: DateTime.Utc | null): string {
   if (!value) return "No trace records";
-  const relative = formatRelativeTime(DateTime.formatIso(value));
-  return relative.suffix ? `${relative.value} ${relative.suffix}` : relative.value;
+  return formatRelativeTimeLabel(DateTime.formatIso(value));
 }
 
 function formatRelativeNoWrap(value: DateTime.Utc | null): string {
@@ -755,12 +754,16 @@ function ProcessResourceHistoryTable({
 
 function DiagnosticsLastChecked({ checkedAt }: { checkedAt: DateTime.Utc | null }) {
   useRelativeTimeTick();
-  const relative = checkedAt ? formatRelativeTime(DateTime.formatIso(checkedAt)) : null;
+  const relative = getRelativeTimeState(checkedAt ? DateTime.formatIso(checkedAt) : null);
 
-  if (!relative) {
+  if (relative.status === "missing") {
     return <span className="text-[11px] text-muted-foreground/50">Checking</span>;
   }
 
+  if (relative.status === "invalid") {
+    return <span className="text-[11px] text-muted-foreground/50">Checked unavailable</span>;
+  }
+
   return (
     <span className="text-[11px] text-muted-foreground/60">
       {relative.suffix ? (
diff --git a/apps/web/src/components/settings/SettingsPanels.tsx b/apps/web/src/components/settings/SettingsPanels.tsx
index 40017d563143..5b29c5494cc7 100644
--- a/apps/web/src/components/settings/SettingsPanels.tsx
+++ b/apps/web/src/components/settings/SettingsPanels.tsx
@@ -58,7 +58,7 @@ import {
 import { usePrimaryEnvironment } from "../../state/environments";
 import { useProjects } from "../../state/entities";
 import { useArchivedThreadSnapshots } from "../../lib/archivedThreadsState";
-import { formatRelativeTime, formatRelativeTimeLabel } from "../../timestampFormat";
+import { formatRelativeTimeLabel, getRelativeTimeState } from "../../timestampFormat";
 import { Button } from "../ui/button";
 import { DraftInput } from "../ui/draft-input";
 import { Select, SelectItem, SelectPopup, SelectTrigger, SelectValue } from "../ui/select";
@@ -134,12 +134,16 @@ const PROVIDER_SETTINGS = DRIVER_OPTIONS.map((definition) => ({
 
 function ProviderLastChecked({ lastCheckedAt }: { lastCheckedAt: string | null }) {
   useRelativeTimeTick();
-  const lastCheckedRelative = lastCheckedAt ? formatRelativeTime(lastCheckedAt) : null;
+  const lastCheckedRelative = getRelativeTimeState(lastCheckedAt);
 
-  if (!lastCheckedRelative) {
+  if (lastCheckedRelative.status === "missing") {
     return null;
   }
 
+  if (lastCheckedRelative.status === "invalid") {
+    return <span className="text-[11px] text-muted-foreground/50">Checked unavailable</span>;
+  }
+
   return (
     <span className="text-[11px] text-muted-foreground/60">
       {lastCheckedRelative.suffix ? (
@@ -401,6 +405,10 @@ export function useSettingsRestore(onRestored?: () => void) {
       ...(settings.enableAssistantStreaming !== DEFAULT_UNIFIED_SETTINGS.enableAssistantStreaming
         ? ["Assistant output"]
         : []),
+      ...(settings.enableProviderUpdateChecks !==
+      DEFAULT_UNIFIED_SETTINGS.enableProviderUpdateChecks
+        ? ["Provider update checks"]
+        : []),
       ...(Duration.toMillis(settings.automaticGitFetchInterval) !==
       Duration.toMillis(DEFAULT_UNIFIED_SETTINGS.automaticGitFetchInterval)
         ? ["Automatic Git fetch interval"]
@@ -434,6 +442,7 @@ export function useSettingsRestore(onRestored?: () => void) {
       settings.diffIgnoreWhitespace,
       settings.automaticGitFetchInterval,
       settings.enableAssistantStreaming,
+      settings.enableProviderUpdateChecks,
       settings.sidebarThreadPreviewCount,
       settings.timestampFormat,
       settings.wordWrap,
@@ -459,6 +468,7 @@ export function useSettingsRestore(onRestored?: () => void) {
       sidebarThreadPreviewCount: DEFAULT_UNIFIED_SETTINGS.sidebarThreadPreviewCount,
       autoOpenPlanSidebar: DEFAULT_UNIFIED_SETTINGS.autoOpenPlanSidebar,
       enableAssistantStreaming: DEFAULT_UNIFIED_SETTINGS.enableAssistantStreaming,
+      enableProviderUpdateChecks: DEFAULT_UNIFIED_SETTINGS.enableProviderUpdateChecks,
       automaticGitFetchInterval: DEFAULT_UNIFIED_SETTINGS.automaticGitFetchInterval,
       defaultThreadEnvMode: DEFAULT_UNIFIED_SETTINGS.defaultThreadEnvMode,
       newWorktreesStartFromOrigin: DEFAULT_UNIFIED_SETTINGS.newWorktreesStartFromOrigin,
diff --git a/apps/web/src/components/sidebar/SidebarUpdatePill.tsx b/apps/web/src/components/sidebar/SidebarUpdatePill.tsx
index c3ac56d10928..fc15862fa46d 100644
--- a/apps/web/src/components/sidebar/SidebarUpdatePill.tsx
+++ b/apps/web/src/components/sidebar/SidebarUpdatePill.tsx
@@ -15,8 +15,48 @@ import {
   shouldToastDesktopUpdateActionResult,
 } from "../desktopUpdate.logic";
 import { Alert, AlertDescription, AlertTitle } from "../ui/alert";
+import { Separator } from "../ui/separator";
 import { Tooltip, TooltipPopup, TooltipTrigger } from "../ui/tooltip";
 
+function SidebarUpdateReleaseNotesTooltip({
+  state,
+  tooltip,
+}: {
+  readonly state: NonNullable<ReturnType<typeof useDesktopUpdateState>>;
+  readonly tooltip: string;
+}) {
+  if (state.channel !== "nightly" || state.releaseNotes.length === 0) {
+    return <>{tooltip}</>;
+  }
+
+  return (
+    <div className="w-120 max-w-[calc(100vw-2rem)] text-left">
+      <div className="px-1">
+        <div className="text-sm leading-5 font-medium">{tooltip}</div>
+      </div>
+      <div className="pointer-events-auto max-h-[min(28rem,calc(100vh-6rem))] overflow-y-auto px-1 pt-4 pb-1">
+        {state.releaseNotes.map((releaseNote, index) => (
+          <div key={releaseNote.version}>
+            {index > 0 && <Separator className="my-3 bg-border/60" />}
+            <section>
+              <h3 className="text-muted-foreground text-xs leading-4 font-semibold">
+                {index === 0 ? "What's changed" : `Changes in ${releaseNote.version}`}
+              </h3>
+              <ul className="mt-2 space-y-1.5 pl-4 text-xs leading-5 text-popover-foreground/90">
+                {releaseNote.items.map((item, itemIndex) => (
+                  <li className="list-disc break-words" key={`${releaseNote.version}-${itemIndex}`}>
+                    {item}
+                  </li>
+                ))}
+              </ul>
+            </section>
+          </div>
+        ))}
+      </div>
+    </div>
+  );
+}
+
 export function SidebarUpdatePill() {
   const state = useDesktopUpdateState();
   const [dismissed, setDismissed] = useState(false);
@@ -151,7 +191,21 @@ export function SidebarUpdatePill() {
                 </button>
               }
             />
-            <TooltipPopup side="top">{tooltip}</TooltipPopup>
+            <TooltipPopup
+              align="start"
+              className={
+                state?.channel === "nightly" && state.releaseNotes.length > 0
+                  ? "max-w-none text-balance"
+                  : undefined
+              }
+              side="top"
+            >
+              {state ? (
+                <SidebarUpdateReleaseNotesTooltip state={state} tooltip={tooltip} />
+              ) : (
+                tooltip
+              )}
+            </TooltipPopup>
           </Tooltip>
           {action === "download" && (
             <Tooltip>
diff --git a/apps/web/src/composer-logic.test.ts b/apps/web/src/composer-logic.test.ts
index 19b7f43f8c8d..99ac6bba7163 100644
--- a/apps/web/src/composer-logic.test.ts
+++ b/apps/web/src/composer-logic.test.ts
@@ -8,9 +8,24 @@ import {
   isCollapsedCursorAdjacentToInlineToken,
   parseStandaloneComposerSlashCommand,
   replaceTextRange,
+  shouldSubmitComposerOnEnter,
 } from "./composer-logic";
 import { INLINE_TERMINAL_CONTEXT_PLACEHOLDER } from "./lib/terminalContext";
 
+describe("shouldSubmitComposerOnEnter", () => {
+  it("submits plain Enter on desktop", () => {
+    expect(shouldSubmitComposerOnEnter({ isMobileViewport: false, shiftKey: false })).toBe(true);
+  });
+
+  it("inserts a newline for plain Enter on mobile", () => {
+    expect(shouldSubmitComposerOnEnter({ isMobileViewport: true, shiftKey: false })).toBe(false);
+  });
+
+  it("inserts a newline for Shift+Enter", () => {
+    expect(shouldSubmitComposerOnEnter({ isMobileViewport: false, shiftKey: true })).toBe(false);
+  });
+});
+
 describe("detectComposerTrigger", () => {
   it("detects @path trigger at cursor", () => {
     const text = "Please check @src/com";
diff --git a/apps/web/src/composer-logic.ts b/apps/web/src/composer-logic.ts
index 46b2c964ae87..2d1d3aed3b1e 100644
--- a/apps/web/src/composer-logic.ts
+++ b/apps/web/src/composer-logic.ts
@@ -11,6 +11,13 @@ export interface ComposerTrigger {
   rangeEnd: number;
 }
 
+export function shouldSubmitComposerOnEnter(input: {
+  isMobileViewport: boolean;
+  shiftKey: boolean;
+}): boolean {
+  return !input.isMobileViewport && !input.shiftKey;
+}
+
 const isInlineTokenSegment = (
   segment:
     | { type: "text"; text: string }
diff --git a/apps/web/src/contextMenuFallback.test.ts b/apps/web/src/contextMenuFallback.test.ts
index 56b4596b9f02..29596e72a9ff 100644
--- a/apps/web/src/contextMenuFallback.test.ts
+++ b/apps/web/src/contextMenuFallback.test.ts
@@ -196,6 +196,23 @@ describe("showContextMenuFallback", () => {
     await expect(selectionPromise).resolves.toBe("rename");
   });
 
+  it("ignores a click from the gesture that opened the menu", async () => {
+    let enablePointerSelection: ((time: number) => void) | undefined;
+    vi.stubGlobal("requestAnimationFrame", (callback: (time: number) => void) => {
+      enablePointerSelection = callback;
+      return 0;
+    });
+
+    const selectionPromise = showContextMenuFallback([{ id: "rename", label: "Rename" }]);
+    const renameButton = findButton("Rename");
+
+    renameButton?.dispatchEvent(new MouseEvent("click", { bubbles: true }));
+    enablePointerSelection?.(0);
+    renameButton?.dispatchEvent(new MouseEvent("click", { bubbles: true }));
+
+    await expect(selectionPromise).resolves.toBe("rename");
+  });
+
   it("opens nested submenus and resolves the clicked leaf id", async () => {
     const selectionPromise = showContextMenuFallback([
       {
diff --git a/apps/web/src/contextMenuFallback.ts b/apps/web/src/contextMenuFallback.ts
index a301e0c92c8b..9b3bb94dbcef 100644
--- a/apps/web/src/contextMenuFallback.ts
+++ b/apps/web/src/contextMenuFallback.ts
@@ -272,7 +272,9 @@ export function showContextMenuFallback<T extends string>(
             button.addEventListener("mouseenter", () => {
               closeMenusFromLevel(level + 1);
             });
-            button.addEventListener("click", () => cleanup(item.id));
+            button.addEventListener("click", () => {
+              if (canDismissFromPointer) cleanup(item.id);
+            });
           }
         }
 
diff --git a/apps/web/src/index.css b/apps/web/src/index.css
index 433f94a71691..f3f32c46436d 100644
--- a/apps/web/src/index.css
+++ b/apps/web/src/index.css
@@ -6,6 +6,7 @@
 
 :root {
   --app-scrollbar-width: 6px;
+  --desktop-window-right-resize-inset: 0px;
   --workspace-topbar-height: 52px;
   --workspace-controls-top: 0px;
   --workspace-controls-left: calc(env(safe-area-inset-left) + 0.75rem);
@@ -387,6 +388,11 @@ body {
   overflow-y: hidden;
   overscroll-behavior-y: none;
   padding-top: max(env(safe-area-inset-top), 0px);
+  padding-right: var(--desktop-window-right-resize-inset);
+}
+
+.electron-windows {
+  --desktop-window-right-resize-inset: 6px;
 }
 
 /* App-chrome grain. Baked into each surface's own background (behind
diff --git a/apps/web/src/lib/windowControlsOverlay.ts b/apps/web/src/lib/windowControlsOverlay.ts
index 8f9ae786b0e0..42f9f13c7cda 100644
--- a/apps/web/src/lib/windowControlsOverlay.ts
+++ b/apps/web/src/lib/windowControlsOverlay.ts
@@ -1,4 +1,8 @@
+import { isWindowsPlatform } from "./utils";
+
 const WCO_CLASS_NAME = "wco";
+const ELECTRON_CLASS_NAME = "electron";
+const ELECTRON_WINDOWS_CLASS_NAME = "electron-windows";
 
 interface WindowControlsOverlayLike {
   readonly visible: boolean;
@@ -38,3 +42,25 @@ export function syncDocumentWindowControlsOverlayClass(): () => void {
     overlay.removeEventListener("geometrychange", update);
   };
 }
+
+export function getElectronPlatformClassNames(
+  platform: string,
+):
+  | readonly [typeof ELECTRON_CLASS_NAME]
+  | readonly [typeof ELECTRON_CLASS_NAME, typeof ELECTRON_WINDOWS_CLASS_NAME] {
+  return isWindowsPlatform(platform)
+    ? [ELECTRON_CLASS_NAME, ELECTRON_WINDOWS_CLASS_NAME]
+    : [ELECTRON_CLASS_NAME];
+}
+
+export function syncDocumentElectronPlatformClasses(platform: string): () => void {
+  if (typeof document === "undefined") {
+    return () => {};
+  }
+
+  const classNames = getElectronPlatformClassNames(platform);
+  document.documentElement.classList.add(...classNames);
+  return () => {
+    document.documentElement.classList.remove(...classNames);
+  };
+}
diff --git a/apps/web/src/main.tsx b/apps/web/src/main.tsx
index 5db89c94724f..f37da2e3b834 100644
--- a/apps/web/src/main.tsx
+++ b/apps/web/src/main.tsx
@@ -19,7 +19,10 @@ import { APP_DISPLAY_NAME } from "./branding";
 import { getAppSettingsSnapshot } from "./appSettings";
 import { applyAccentColorToDocument } from "./accentColor";
 import { applyThemeConfigToDocument } from "./themeConfig";
-import { syncDocumentWindowControlsOverlayClass } from "./lib/windowControlsOverlay";
+import {
+  syncDocumentElectronPlatformClasses,
+  syncDocumentWindowControlsOverlayClass,
+} from "./lib/windowControlsOverlay";
 import { AppRoot } from "./AppRoot";
 
 // Electron loads the app from a file-backed shell, so hash history avoids path resolution issues.
@@ -28,6 +31,7 @@ const history = isElectron ? createHashHistory() : createBrowserHistory();
 const router = getRouter(history);
 
 if (isElectron) {
+  syncDocumentElectronPlatformClasses(navigator.platform);
   syncDocumentWindowControlsOverlayClass();
 }
 
diff --git a/apps/web/src/state/desktopUpdate.test.ts b/apps/web/src/state/desktopUpdate.test.ts
index a2bcbd19a33f..0c05b2d45395 100644
--- a/apps/web/src/state/desktopUpdate.test.ts
+++ b/apps/web/src/state/desktopUpdate.test.ts
@@ -15,6 +15,7 @@ const baseState: DesktopUpdateState = {
   runningUnderArm64Translation: false,
   availableVersion: null,
   downloadedVersion: null,
+  releaseNotes: [],
   downloadPercent: null,
   checkedAt: null,
   message: null,
diff --git a/apps/web/src/timestampFormat.test.ts b/apps/web/src/timestampFormat.test.ts
index c68d5b7ee465..c2fe4b62714f 100644
--- a/apps/web/src/timestampFormat.test.ts
+++ b/apps/web/src/timestampFormat.test.ts
@@ -3,7 +3,13 @@ import { afterEach, beforeEach, describe, expect, it, vi } from "vite-plus/test"
 import {
   formatElapsedDurationLabel,
   formatExpiresInLabel,
+  formatRelativeTime,
+  formatRelativeTimeLabel,
+  formatRelativeTimeUntil,
   formatRelativeTimeUntilLabel,
+  formatShortTimestamp,
+  formatTimestamp,
+  getRelativeTimeState,
   getTimestampFormatOptions,
 } from "./timestampFormat";
 
@@ -90,6 +96,60 @@ describe("formatExpiresInLabel", () => {
   });
 });
 
+describe("invalid timestamp inputs", () => {
+  it("returns an empty timestamp instead of throwing", () => {
+    expect(() => formatTimestamp("not-a-date", "12-hour")).not.toThrow();
+    expect(formatTimestamp("not-a-date", "12-hour")).toBe("");
+  });
+
+  it("returns an empty short timestamp instead of throwing", () => {
+    expect(() => formatShortTimestamp("not-a-date", "12-hour")).not.toThrow();
+    expect(formatShortTimestamp("not-a-date", "12-hour")).toBe("");
+  });
+
+  it("returns an empty relative time label instead of a NaN label", () => {
+    expect(formatRelativeTime("not-a-date")).toBeNull();
+    expect(formatRelativeTimeLabel("not-a-date")).toBe("");
+  });
+
+  it("distinguishes missing and invalid relative time state", () => {
+    expect(getRelativeTimeState(null)).toEqual({ status: "missing" });
+    expect(getRelativeTimeState("not-a-date")).toEqual({ status: "invalid" });
+  });
+
+  it("returns an empty elapsed duration instead of a NaN label", () => {
+    expect(formatElapsedDurationLabel("not-a-date")).toBe("");
+  });
+
+  it("returns an empty relative time until label instead of a NaN label", () => {
+    expect(formatRelativeTimeUntil("not-a-date")).toBeNull();
+    expect(formatRelativeTimeUntilLabel("not-a-date")).toBe("");
+  });
+
+  it("returns an empty expires-in label instead of a NaN label", () => {
+    expect(formatExpiresInLabel("not-a-date")).toBe("");
+  });
+});
+
+describe("getRelativeTimeState", () => {
+  beforeEach(() => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-04-07T12:00:00.000Z"));
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  it("returns relative parts for valid timestamps", () => {
+    expect(getRelativeTimeState("2026-04-07T11:45:00.000Z")).toEqual({
+      status: "relative",
+      value: "15m",
+      suffix: "ago",
+    });
+  });
+});
+
 describe("formatElapsedDurationLabel", () => {
   beforeEach(() => {
     vi.useFakeTimers();
diff --git a/apps/web/src/timestampFormat.ts b/apps/web/src/timestampFormat.ts
index bcf8dc9c1f20..31cc41798ebe 100644
--- a/apps/web/src/timestampFormat.ts
+++ b/apps/web/src/timestampFormat.ts
@@ -40,8 +40,15 @@ function getTimestampFormatter(
   return formatter;
 }
 
+function parseTimestampDate(isoDate: string): Date | null {
+  const date = new Date(isoDate);
+  return Number.isNaN(date.getTime()) ? null : date;
+}
+
 export function formatTimestamp(isoDate: string, timestampFormat: TimestampFormat): string {
-  return getTimestampFormatter(timestampFormat, true).format(new Date(isoDate));
+  const date = parseTimestampDate(isoDate);
+  if (!date) return "";
+  return getTimestampFormatter(timestampFormat, true).format(date);
 }
 
 const monthNameFormatter = new Intl.DateTimeFormat(undefined, { month: "long" });
@@ -69,8 +76,8 @@ export function formatChatTimestampTooltip(
   isoDate: string,
   timestampFormat: TimestampFormat,
 ): string {
-  const date = new Date(isoDate);
-  if (Number.isNaN(date.getTime())) return "";
+  const date = parseTimestampDate(isoDate);
+  if (!date) return "";
   const time = formatShortTimestamp(isoDate, timestampFormat);
   const day = date.getDate();
   const month = monthNameFormatter.format(date);
@@ -79,7 +86,9 @@ export function formatChatTimestampTooltip(
 }
 
 export function formatShortTimestamp(isoDate: string, timestampFormat: TimestampFormat): string {
-  return getTimestampFormatter(timestampFormat, false).format(new Date(isoDate));
+  const date = parseTimestampDate(isoDate);
+  if (!date) return "";
+  return getTimestampFormatter(timestampFormat, false).format(date);
 }
 
 /**
@@ -87,8 +96,16 @@ export function formatShortTimestamp(isoDate: string, timestampFormat: Timestamp
  * Returns `{ value: "20s", suffix: "ago" }` or `{ value: "just now", suffix: null }`
  * so callers can style the numeric portion independently.
  */
-export function formatRelativeTime(isoDate: string): { value: string; suffix: string | null } {
-  const diffMs = Date.now() - new Date(isoDate).getTime();
+type RelativeTimeParts = { value: string; suffix: string | null };
+export type RelativeTimeState =
+  | { status: "missing" }
+  | { status: "invalid" }
+  | { status: "relative"; value: string; suffix: string | null };
+
+export function formatRelativeTime(isoDate: string): RelativeTimeParts | null {
+  const date = parseTimestampDate(isoDate);
+  if (!date) return null;
+  const diffMs = Date.now() - date.getTime();
   if (diffMs < 0) return { value: "just now", suffix: null };
   const seconds = Math.floor(diffMs / 1000);
   if (seconds < 60) return { value: "just now", suffix: null };
@@ -100,9 +117,17 @@ export function formatRelativeTime(isoDate: string): { value: string; suffix: st
   return { value: `${days}d`, suffix: "ago" };
 }
 
-export function formatRelativeTimeLabel(isoDate: string): string {
-  const { value, suffix } = formatRelativeTime(isoDate);
-  return suffix ? `${value} ${suffix}` : value;
+export function formatRelativeTimeLabel(isoDate: string) {
+  const relative = formatRelativeTime(isoDate);
+  if (!relative) return "";
+  return relative.suffix ? `${relative.value} ${relative.suffix}` : relative.value;
+}
+
+export function getRelativeTimeState(isoDate: string | null): RelativeTimeState {
+  if (!isoDate) return { status: "missing" };
+  const relative = formatRelativeTime(isoDate);
+  if (!relative) return { status: "invalid" };
+  return { status: "relative", ...relative };
 }
 
 /**
@@ -110,7 +135,9 @@ export function formatRelativeTimeLabel(isoDate: string): string {
  * Useful for labels like "Connected for 3m".
  */
 export function formatElapsedDurationLabel(isoDate: string, nowMs: number = Date.now()): string {
-  const diffMs = nowMs - new Date(isoDate).getTime();
+  const date = parseTimestampDate(isoDate);
+  if (!date) return "";
+  const diffMs = nowMs - date.getTime();
   if (diffMs <= 0) return "just now";
 
   const seconds = Math.floor(diffMs / 1000);
@@ -130,8 +157,10 @@ export function formatElapsedDurationLabel(isoDate: string, nowMs: number = Date
 /**
  * Relative time until an ISO instant (e.g. expiry). Mirrors {@link formatRelativeTime} but for future times.
  */
-export function formatRelativeTimeUntil(isoDate: string): { value: string; suffix: string | null } {
-  const diffMs = new Date(isoDate).getTime() - Date.now();
+export function formatRelativeTimeUntil(isoDate: string): RelativeTimeParts | null {
+  const date = parseTimestampDate(isoDate);
+  if (!date) return null;
+  const diffMs = date.getTime() - Date.now();
   if (diffMs <= 0) return { value: "Expired", suffix: null };
   const seconds = Math.floor(diffMs / 1000);
   if (seconds < 5) return { value: "Soon", suffix: null };
@@ -146,6 +175,7 @@ export function formatRelativeTimeUntil(isoDate: string): { value: string; suffi
 
 export function formatRelativeTimeUntilLabel(isoDate: string): string {
   const relative = formatRelativeTimeUntil(isoDate);
+  if (!relative) return "";
   return relative.suffix ? `${relative.value} ${relative.suffix}` : relative.value;
 }
 
@@ -154,7 +184,9 @@ export function formatRelativeTimeUntilLabel(isoDate: string): string {
  * Pass `nowMs` when a parent tick drives re-renders so the diff matches that snapshot.
  */
 export function formatExpiresInLabel(isoDate: string, nowMs: number = Date.now()): string {
-  const diffMs = new Date(isoDate).getTime() - nowMs;
+  const date = parseTimestampDate(isoDate);
+  if (!date) return "";
+  const diffMs = date.getTime() - nowMs;
   if (diffMs <= 0) return "Expired";
 
   const totalSeconds = Math.floor(diffMs / 1000);
diff --git a/assets/README.md b/assets/README.md
new file mode 100644
index 000000000000..8a7e3c5f20a8
--- /dev/null
+++ b/assets/README.md
@@ -0,0 +1,50 @@
+# Brand icons
+
+The three Icon Composer projects are the source of truth for full application icons:
+
+- `dev/app-icon.icon`
+- `nightly/app-icon.icon`
+- `prod/app-icon.icon`
+
+Each project uses `text.svg` for the T3 mark and `background.svg` when the background is a vector layer. Additional layers use semantic names that describe their role and placement.
+
+Run `vp run icons:export` from the repository root to regenerate the tracked iOS, Linux, Windows, and web assets. Run `vp run icons:check` to verify that those generated assets match their sources without changing files.
+
+Exporting requires Icon Composer 2 or newer on macOS. The script selects the newest compatible exporter from Xcode or a standalone Icon Composer installation and pins design generation 26. Set `ICON_COMPOSER_TOOL` to the full path of `Icon Composer.app/Contents/Executables/ictool` to override automatic discovery.
+
+## macOS exports
+
+Icon Composer's command-line exporter does not expose the `macOS pre-Tahoe` preset. A plain command-line `macOS` export is full bleed and is not suitable for the desktop app, so the export script intentionally leaves the tracked macOS PNGs unchanged and prints a reminder after every run.
+
+After changing an Icon Composer project, open it in Icon Composer and export the macOS PNG with exactly these settings:
+
+- Platform: `macOS pre-Tahoe`
+- Appearance: `Default`
+- Size: `1024pt`
+- Scale: `1×`
+
+Save the three exports to:
+
+- `dev/app-icon.icon` -> `dev/blueprint-macos-1024.png`
+- `nightly/app-icon.icon` -> `nightly/nightly-macos-1024.png`
+- `prod/app-icon.icon` -> `prod/black-macos-1024.png`
+
+The result must be a 1024×1024 PNG with the classic macOS safe area: the opaque icon body is 824×824, inset 100 pixels on every side, with only the native Icon Composer shadow extending into the surrounding transparent canvas.
+
+To have Codex perform the native exports, paste this prompt into a task opened at the repository root:
+
+```text
+Use [@Computer](plugin://computer-use@openai-bundled) and the Icon Composer app to export the three macOS app icons in this repository.
+
+For each project below, use Platform: macOS pre-Tahoe, Appearance: Default, Size: 1024pt, and Scale: 1×, then save the PNG to the exact destination:
+
+- assets/dev/app-icon.icon -> assets/dev/blueprint-macos-1024.png
+- assets/nightly/app-icon.icon -> assets/nightly/nightly-macos-1024.png
+- assets/prod/app-icon.icon -> assets/prod/black-macos-1024.png
+
+Do not resize, composite, or otherwise post-process the exported PNGs.
+
+Verify every result is 1024×1024 and has the classic macOS safe area: an 824×824 opaque body inset 100px on every side, with only Icon Composer's native shadow extending beyond it.
+```
+
+Do not edit the generated PNG or ICO files directly.
diff --git a/assets/dev/app-icon.icon/Assets/annotations.svg b/assets/dev/app-icon.icon/Assets/annotations.svg
new file mode 100644
index 000000000000..dffde33559ea
--- /dev/null
+++ b/assets/dev/app-icon.icon/Assets/annotations.svg
@@ -0,0 +1,37 @@
+<svg width="128" height="128" viewBox="0 0 128 128" fill="none" xmlns="http://www.w3.org/2000/svg">
+  <defs>
+    <marker id="arrowStart" markerWidth="5" markerHeight="5" refX="1.2" refY="2.5" orient="auto" markerUnits="strokeWidth">
+      <path d="M4.5 0.6L1 2.5L4.5 4.4" fill="none" stroke="#DDF7FF" stroke-width="0.8" stroke-linecap="round"/>
+    </marker>
+    <marker id="arrowEnd" markerWidth="5" markerHeight="5" refX="3.8" refY="2.5" orient="auto" markerUnits="strokeWidth">
+      <path d="M0.5 0.6L4 2.5L0.5 4.4" fill="none" stroke="#DDF7FF" stroke-width="0.8" stroke-linecap="round"/>
+    </marker>
+  </defs>
+
+  <g stroke="#DDF7FF" stroke-linecap="round" stroke-linejoin="round">
+    <g opacity="0.9" stroke-width="0.44">
+      <path d="M15.5309 31V25.6M64.3309 31V25.6M68.1653 31V25.6M107.365 31V25.6"/>
+      <path d="M16.9 27.2H62.96" marker-start="url(#arrowStart)" marker-end="url(#arrowEnd)"/>
+      <path d="M69.54 27.2H105.99" marker-start="url(#arrowStart)" marker-end="url(#arrowEnd)"/>
+      <path d="M33.4509 97.3V103M46.4109 97.3V103M65.3653 97.3V103M109.925 97.3V103"/>
+      <path d="M34.82 101.1H45.04" marker-start="url(#arrowStart)" marker-end="url(#arrowEnd)"/>
+      <path d="M66.74 101.1H108.55" marker-start="url(#arrowStart)" marker-end="url(#arrowEnd)"/>
+      <path d="M10.2 37H6.1M10.2 47.6H6.1M10.2 93H6.1"/>
+      <path d="M7.9 38.4V46.2" marker-start="url(#arrowStart)" marker-end="url(#arrowEnd)"/>
+      <path d="M7.9 49V91.6" marker-start="url(#arrowStart)" marker-end="url(#arrowEnd)"/>
+    </g>
+
+    <g opacity="0.58" stroke-width="0.34">
+      <path d="M12.5 35.1H66.8M39.9309 94.8V44.5M64.3309 34.2V49.9M68.1653 34.2V49.9" stroke-dasharray="1.6 1.6"/>
+      <path d="M65.3653 65.2H109.925M87.2 32.7V98.2" stroke-dasharray="1.2 2"/>
+      <circle cx="87.2" cy="65.2" r="20.8"/>
+      <circle cx="87.2" cy="65.2" r="1.1"/>
+    </g>
+
+    <g opacity="0.76" stroke-width="0.4">
+      <path d="M24 20V24M22 22H26M101 17V21M99 19H103M114 106V110M112 108H116"/>
+      <path d="M54 107L57 110M57 107L54 110M16 74L19 77M19 74L16 77"/>
+      <path d="M74 22H82M78 18V26" stroke-dasharray="0.7 1.1"/>
+    </g>
+  </g>
+</svg>
diff --git a/assets/dev/app-icon.icon/Assets/background.svg b/assets/dev/app-icon.icon/Assets/background.svg
new file mode 100644
index 000000000000..db5c319d607d
--- /dev/null
+++ b/assets/dev/app-icon.icon/Assets/background.svg
@@ -0,0 +1,51 @@
+<svg width="128" height="128" viewBox="0 0 128 128" fill="none" xmlns="http://www.w3.org/2000/svg">
+  <defs>
+    <linearGradient id="paper" x1="36" y1="0" x2="92" y2="128" gradientUnits="userSpaceOnUse">
+      <stop stop-color="#67C2FF"/>
+      <stop offset="0.44" stop-color="#347FF8"/>
+      <stop offset="1" stop-color="#1538D0"/>
+    </linearGradient>
+    <radialGradient id="cyanGlow" cx="0" cy="0" r="1" gradientUnits="userSpaceOnUse" gradientTransform="translate(92 22) rotate(137) scale(78 70)">
+      <stop stop-color="#D4F6FF" stop-opacity="0.62"/>
+      <stop offset="0.52" stop-color="#65C8FF" stop-opacity="0.24"/>
+      <stop offset="1" stop-color="#276AF1" stop-opacity="0"/>
+    </radialGradient>
+    <radialGradient id="edgeShade" cx="0" cy="0" r="1" gradientUnits="userSpaceOnUse" gradientTransform="translate(64 58) rotate(90) scale(77)">
+      <stop offset="0.68" stop-color="#102EBC" stop-opacity="0"/>
+      <stop offset="1" stop-color="#061A88" stop-opacity="0.48"/>
+    </radialGradient>
+    <pattern id="minorGrid" width="4" height="4" patternUnits="userSpaceOnUse">
+      <path d="M4 0H0V4" stroke="#D9F7FF" stroke-width="0.18" opacity="0.38"/>
+    </pattern>
+    <pattern id="majorGrid" width="16" height="16" patternUnits="userSpaceOnUse">
+      <rect width="16" height="16" fill="url(#minorGrid)"/>
+      <path d="M16 0H0V16" stroke="#F0FCFF" stroke-width="0.34" opacity="0.52"/>
+    </pattern>
+    <clipPath id="frame">
+      <rect width="128" height="128" rx="10"/>
+    </clipPath>
+  </defs>
+
+  <g clip-path="url(#frame)">
+    <rect width="128" height="128" fill="url(#paper)"/>
+    <rect width="128" height="128" fill="url(#cyanGlow)"/>
+    <rect x="4" y="4" width="120" height="120" fill="url(#majorGrid)" opacity="0.96"/>
+    <path d="M64 4V124M4 64H124" stroke="#F0FCFF" stroke-width="0.3" opacity="0.46"/>
+    <rect x="5.75" y="5.75" width="116.5" height="116.5" rx="5.5" stroke="#F1FCFF" stroke-width="0.5" opacity="0.66"/>
+
+    <g stroke="#BFE9F7" stroke-linecap="round" opacity="0.2">
+      <path d="M14 19L24 12M17 22L29 13" stroke-width="0.5"/>
+      <path d="M106 25L115 18M104 30L118 20" stroke-width="0.38"/>
+      <path d="M11 108L23 101M16 113L28 105" stroke-width="0.42"/>
+      <path d="M102 113L116 104M107 116L120 108" stroke-width="0.46"/>
+    </g>
+    <g fill="#D7F4FF" opacity="0.22">
+      <circle cx="18" cy="30" r="0.45"/>
+      <circle cx="112" cy="38" r="0.35"/>
+      <circle cx="22" cy="98" r="0.3"/>
+      <circle cx="109" cy="94" r="0.5"/>
+      <circle cx="94" cy="14" r="0.32"/>
+    </g>
+    <rect width="128" height="128" fill="url(#edgeShade)"/>
+  </g>
+</svg>
diff --git a/assets/dev/app-icon.icon/Assets/text.svg b/assets/dev/app-icon.icon/Assets/text.svg
new file mode 100644
index 000000000000..0b1825f2ef47
--- /dev/null
+++ b/assets/dev/app-icon.icon/Assets/text.svg
@@ -0,0 +1,3 @@
+<svg width="128" height="128" viewBox="0 0 128 128" fill="none" xmlns="http://www.w3.org/2000/svg">
+  <path d="M33.4509 93V47.56H15.5309V37H64.3309V47.56H46.4109V93H33.4509ZM86.7253 93.96C82.832 93.96 78.9653 93.4533 75.1253 92.44C71.2853 91.3733 68.032 89.88 65.3653 87.96L70.4053 78.04C72.5386 79.5867 75.0186 80.8133 77.8453 81.72C80.672 82.6267 83.5253 83.08 86.4053 83.08C89.6586 83.08 92.2186 82.44 94.0853 81.16C95.952 79.88 96.8853 78.12 96.8853 75.88C96.8853 73.7467 96.0586 72.0667 94.4053 70.84C92.752 69.6133 90.0853 69 86.4053 69H80.4853V60.44L96.0853 42.76L97.5253 47.4H68.1653V37H107.365V45.4L91.8453 63.08L85.2853 59.32H89.0453C95.9253 59.32 101.125 60.8667 104.645 63.96C108.165 67.0533 109.925 71.0267 109.925 75.88C109.925 79.0267 109.099 81.9867 107.445 84.76C105.792 87.48 103.259 89.6933 99.8453 91.4C96.432 93.1067 92.0586 93.96 86.7253 93.96Z" fill="white"/>
+</svg>
diff --git a/apps/mobile/assets/icon-composer-dev.icon/icon.json b/assets/dev/app-icon.icon/icon.json
similarity index 53%
rename from apps/mobile/assets/icon-composer-dev.icon/icon.json
rename to assets/dev/app-icon.icon/icon.json
index fd3fb6819a91..ff7d43d78112 100644
--- a/apps/mobile/assets/icon-composer-dev.icon/icon.json
+++ b/assets/dev/app-icon.icon/icon.json
@@ -6,35 +6,40 @@
     {
       "layers": [
         {
-          "hidden": false,
-          "image-name": "gpt-image-1.5-jd70szmrd03p36z4zv48ycsbax81egvr.png",
-          "name": "gpt-image-1.5-jd70szmrd03p36z4zv48ycsbax81egvr",
+          "glass": true,
+          "image-name": "text.svg",
+          "name": "Text",
           "position": {
-            "scale": 1.1,
+            "scale": 8.5,
             "translation-in-points": [0, 0]
           }
         },
         {
-          "image-name": "T3.svg",
-          "name": "T3",
+          "glass": false,
+          "image-name": "annotations.svg",
+          "name": "Annotations",
           "position": {
-            "scale": 10,
+            "scale": 8.5,
             "translation-in-points": [0, 0]
           }
         },
         {
-          "hidden": true,
-          "image-name": "Texturelabs_Paper_381XL.jpg",
-          "name": "Texturelabs_Paper_381XL"
+          "glass": true,
+          "image-name": "background.svg",
+          "name": "Background",
+          "position": {
+            "scale": 8.1,
+            "translation-in-points": [0, 0]
+          }
         }
       ],
       "shadow": {
         "kind": "neutral",
-        "opacity": 0.5
+        "opacity": 0.6
       },
       "translucency": {
         "enabled": true,
-        "value": 0.5
+        "value": 0.2
       }
     }
   ],
diff --git a/assets/dev/blueprint-icon-composer.icon/Assets/T3.svg b/assets/dev/blueprint-icon-composer.icon/Assets/T3.svg
deleted file mode 100644
index b12706fdfc23..000000000000
--- a/assets/dev/blueprint-icon-composer.icon/Assets/T3.svg
+++ /dev/null
@@ -1,3 +0,0 @@
-<svg width="77" height="47" viewBox="0 0 77 47" fill="none" xmlns="http://www.w3.org/2000/svg">
-<path d="M14.56 45.5V8.58H1.69082e-06V-3.09944e-06H39.65V8.58H25.09V45.5H14.56ZM57.8454 46.28C54.6821 46.28 51.5404 45.8683 48.4204 45.045C45.3004 44.1783 42.6571 42.965 40.4904 41.405L44.5854 33.345C46.3188 34.6017 48.3338 35.5983 50.6304 36.335C52.9271 37.0717 55.2454 37.44 57.5854 37.44C60.2288 37.44 62.3088 36.92 63.8254 35.88C65.3421 34.84 66.1004 33.41 66.1004 31.59C66.1004 29.8567 65.4288 28.4917 64.0854 27.495C62.7421 26.4983 60.5754 26 57.5854 26H52.7754V19.045L65.4504 4.68L66.6204 8.45H42.7654V-3.09944e-06H74.6154V6.825L62.0054 21.19L56.6754 18.135H59.7304C65.3204 18.135 69.5454 19.3917 72.4054 21.905C75.2654 24.4183 76.6954 27.6467 76.6954 31.59C76.6954 34.1467 76.0238 36.5517 74.6804 38.805C73.3371 41.015 71.2788 42.8133 68.5054 44.2C65.7321 45.5867 62.1788 46.28 57.8454 46.28Z" fill="white"/>
-</svg>
diff --git a/assets/dev/blueprint-icon-composer.icon/Assets/Texturelabs_Paper_381XL.jpg b/assets/dev/blueprint-icon-composer.icon/Assets/Texturelabs_Paper_381XL.jpg
deleted file mode 100644
index d98c41a4e3e8..000000000000
Binary files a/assets/dev/blueprint-icon-composer.icon/Assets/Texturelabs_Paper_381XL.jpg and /dev/null differ
diff --git a/assets/dev/blueprint-icon-composer.icon/Assets/gpt-image-1.5-kn76n9hynne5q3qxy3g91chp2d84t871.png b/assets/dev/blueprint-icon-composer.icon/Assets/gpt-image-1.5-kn76n9hynne5q3qxy3g91chp2d84t871.png
deleted file mode 100644
index fa7700d01c73..000000000000
Binary files a/assets/dev/blueprint-icon-composer.icon/Assets/gpt-image-1.5-kn76n9hynne5q3qxy3g91chp2d84t871.png and /dev/null differ
diff --git a/assets/dev/blueprint-icon-composer.icon/icon.json b/assets/dev/blueprint-icon-composer.icon/icon.json
deleted file mode 100644
index 1c15123dab4f..000000000000
--- a/assets/dev/blueprint-icon-composer.icon/icon.json
+++ /dev/null
@@ -1,47 +0,0 @@
-{
-  "fill": {
-    "solid": "display-p3:0.00000,0.00000,0.00000,1.00000"
-  },
-  "groups": [
-    {
-      "layers": [
-        {
-          "blend-mode": "normal",
-          "fill": "automatic",
-          "glass": true,
-          "hidden": false,
-          "image-name": "gpt-image-1.5-kn76n9hynne5q3qxy3g91chp2d84t871.png",
-          "name": "gpt-image-1.5-kn76n9hynne5q3qxy3g91chp2d84t871",
-          "position": {
-            "scale": 1.05,
-            "translation-in-points": [0, 0]
-          }
-        },
-        {
-          "image-name": "T3.svg",
-          "name": "T3",
-          "position": {
-            "scale": 10,
-            "translation-in-points": [0, 0]
-          }
-        },
-        {
-          "hidden": false,
-          "image-name": "Texturelabs_Paper_381XL.jpg",
-          "name": "Texturelabs_Paper_381XL"
-        }
-      ],
-      "shadow": {
-        "kind": "neutral",
-        "opacity": 0.5
-      },
-      "translucency": {
-        "enabled": true,
-        "value": 0.5
-      }
-    }
-  ],
-  "supported-platforms": {
-    "squares": ["iOS", "macOS"]
-  }
-}
diff --git a/assets/dev/blueprint-ios-1024.png b/assets/dev/blueprint-ios-1024.png
index 51b764ac72ae..a53c8d19aa83 100644
Binary files a/assets/dev/blueprint-ios-1024.png and b/assets/dev/blueprint-ios-1024.png differ
diff --git a/assets/dev/blueprint-macos-1024.png b/assets/dev/blueprint-macos-1024.png
index 7c165fdb851b..68a567058be1 100644
Binary files a/assets/dev/blueprint-macos-1024.png and b/assets/dev/blueprint-macos-1024.png differ
diff --git a/assets/dev/blueprint-universal-1024.png b/assets/dev/blueprint-universal-1024.png
index 51b764ac72ae..a53c8d19aa83 100644
Binary files a/assets/dev/blueprint-universal-1024.png and b/assets/dev/blueprint-universal-1024.png differ
diff --git a/assets/dev/blueprint-web-apple-touch-180.png b/assets/dev/blueprint-web-apple-touch-180.png
index 4a135d22fdbc..3eed25ea6b78 100644
Binary files a/assets/dev/blueprint-web-apple-touch-180.png and b/assets/dev/blueprint-web-apple-touch-180.png differ
diff --git a/assets/dev/blueprint-web-favicon-16x16.png b/assets/dev/blueprint-web-favicon-16x16.png
index 56e0e837131e..a3431b8c6dfe 100644
Binary files a/assets/dev/blueprint-web-favicon-16x16.png and b/assets/dev/blueprint-web-favicon-16x16.png differ
diff --git a/assets/dev/blueprint-web-favicon-32x32.png b/assets/dev/blueprint-web-favicon-32x32.png
index 9e9f31ea9893..862f7629971f 100644
Binary files a/assets/dev/blueprint-web-favicon-32x32.png and b/assets/dev/blueprint-web-favicon-32x32.png differ
diff --git a/assets/dev/blueprint-web-favicon.ico b/assets/dev/blueprint-web-favicon.ico
index e0ee3e1408f0..750da22602ee 100644
Binary files a/assets/dev/blueprint-web-favicon.ico and b/assets/dev/blueprint-web-favicon.ico differ
diff --git a/assets/dev/blueprint-windows.ico b/assets/dev/blueprint-windows.ico
index e0ee3e1408f0..750da22602ee 100644
Binary files a/assets/dev/blueprint-windows.ico and b/assets/dev/blueprint-windows.ico differ
diff --git a/assets/nightly/app-icon.icon/Assets/background.svg b/assets/nightly/app-icon.icon/Assets/background.svg
new file mode 100644
index 000000000000..1ceca91c0236
--- /dev/null
+++ b/assets/nightly/app-icon.icon/Assets/background.svg
@@ -0,0 +1,43 @@
+<svg width="128" height="128" viewBox="0 0 128 128" fill="none" xmlns="http://www.w3.org/2000/svg">
+  <defs>
+    <linearGradient id="night" x1="12" y1="6" x2="116" y2="124" gradientUnits="userSpaceOnUse">
+      <stop stop-color="#07152F"/>
+      <stop offset="0.5" stop-color="#151443"/>
+      <stop offset="1" stop-color="#32155B"/>
+    </linearGradient>
+    <radialGradient id="skyGlow" cx="0" cy="0" r="1" gradientUnits="userSpaceOnUse" gradientTransform="translate(90 28) rotate(137) scale(78 70)">
+      <stop stop-color="#5165D8" stop-opacity="0.4"/>
+      <stop offset="0.5" stop-color="#283075" stop-opacity="0.16"/>
+      <stop offset="1" stop-color="#111635" stop-opacity="0"/>
+    </radialGradient>
+    <radialGradient id="horizonGlow" cx="0" cy="0" r="1" gradientUnits="userSpaceOnUse" gradientTransform="translate(42 127) rotate(-70) scale(68 96)">
+      <stop stop-color="#6646B6" stop-opacity="0.34"/>
+      <stop offset="1" stop-color="#352066" stop-opacity="0"/>
+    </radialGradient>
+    <clipPath id="frame">
+      <rect width="128" height="128" rx="10"/>
+    </clipPath>
+  </defs>
+
+  <g clip-path="url(#frame)">
+    <rect width="128" height="128" fill="url(#night)"/>
+    <rect width="128" height="128" fill="url(#skyGlow)"/>
+    <rect width="128" height="128" fill="url(#horizonGlow)"/>
+
+
+    <!-- A few tiny stars kept to the perimeter so the wordmark stays clear. -->
+    <g fill="#E4EAFF">
+      <circle cx="17" cy="18" r="0.55" fill-opacity="0.82"/>
+      <circle cx="54" cy="14" r="0.4" fill-opacity="0.65"/>
+      <circle cx="116" cy="42" r="0.45" fill-opacity="0.72"/>
+      <circle cx="10" cy="70" r="0.35" fill-opacity="0.56"/>
+      <circle cx="117" cy="88" r="0.4" fill-opacity="0.6"/>
+    </g>
+    <path d="M31 22V24.8M29.6 23.4H32.4" stroke="#EEF2FF" stroke-width="0.5" stroke-linecap="round" opacity="0.72"/>
+    <path d="M111 58V60M110 59H112" stroke="#CBD8FF" stroke-width="0.45" stroke-linecap="round" opacity="0.58"/>
+
+    <!-- Broad horizon remains below the T3 baseline (y=94). -->
+    <path d="M-12 119C14 99 39 99 63 110C87 121 110 116 140 96V140H-12V119Z" fill="#20184E" fill-opacity="0.42"/>
+    <path d="M-12 129C15 111 42 112 66 122C91 132 114 124 140 107V140H-12V129Z" fill="#6946B8" fill-opacity="0.22"/>
+  </g>
+</svg>
diff --git a/assets/nightly/app-icon.icon/Assets/cloud-lower-left.svg b/assets/nightly/app-icon.icon/Assets/cloud-lower-left.svg
new file mode 100644
index 000000000000..d43478860f46
--- /dev/null
+++ b/assets/nightly/app-icon.icon/Assets/cloud-lower-left.svg
@@ -0,0 +1,21 @@
+<svg width="64" height="32" viewBox="0 0 64 32" fill="none" xmlns="http://www.w3.org/2000/svg">
+  <defs>
+    <linearGradient id="cloud" x1="7" y1="10" x2="57" y2="25" gradientUnits="userSpaceOnUse">
+      <stop stop-color="#4EA4FF" stop-opacity="0.62"/>
+      <stop offset="0.52" stop-color="#696FEA" stop-opacity="0.72"/>
+      <stop offset="1" stop-color="#A85BEA" stop-opacity="0.58"/>
+    </linearGradient>
+    <radialGradient id="highlight" cx="0" cy="0" r="1" gradientUnits="userSpaceOnUse" gradientTransform="translate(30 14) rotate(13) scale(27 10)">
+      <stop stop-color="#C8D7FF" stop-opacity="0.4"/>
+      <stop offset="1" stop-color="#8C8EF2" stop-opacity="0"/>
+    </radialGradient>
+    <filter id="soft" x="-8" y="-8" width="80" height="48" filterUnits="userSpaceOnUse" color-interpolation-filters="sRGB">
+      <feGaussianBlur stdDeviation="2.5"/>
+    </filter>
+  </defs>
+
+  <g filter="url(#soft)">
+    <path d="M7 23.5C7 18.9 10.8 15.2 15.5 15.2C16.9 10.7 21.1 7.5 26.1 7.5C31 7.5 35.2 10.5 36.7 14.8C38.5 13.2 40.9 12.2 43.5 12.2C49.1 12.2 53.7 16.4 54.1 21.8C57 22.2 59.2 24 60 26.5H8.2C7.4 25.7 7 24.7 7 23.5Z" fill="url(#cloud)"/>
+    <path d="M11 22.9C12.7 19.8 16 18 19.5 18.5C21 13.4 25.6 10 30.8 10.6C35 11 38.3 13.9 39.4 17.7C43.8 15.5 49 17.3 51.1 21.7C46.2 20.3 41.9 21 37.7 22.1C29.6 24.2 21.5 21.3 11 22.9Z" fill="url(#highlight)"/>
+  </g>
+</svg>
diff --git a/assets/nightly/app-icon.icon/Assets/cloud-upper-right.svg b/assets/nightly/app-icon.icon/Assets/cloud-upper-right.svg
new file mode 100644
index 000000000000..7b094441db15
--- /dev/null
+++ b/assets/nightly/app-icon.icon/Assets/cloud-upper-right.svg
@@ -0,0 +1,21 @@
+<svg width="64" height="32" viewBox="0 0 64 32" fill="none" xmlns="http://www.w3.org/2000/svg">
+  <defs>
+    <linearGradient id="cloud" x1="7" y1="10" x2="57" y2="25" gradientUnits="userSpaceOnUse">
+      <stop stop-color="#4EA4FF" stop-opacity="0.62"/>
+      <stop offset="0.52" stop-color="#696FEA" stop-opacity="0.72"/>
+      <stop offset="1" stop-color="#A85BEA" stop-opacity="0.58"/>
+    </linearGradient>
+    <radialGradient id="highlight" cx="0" cy="0" r="1" gradientUnits="userSpaceOnUse" gradientTransform="translate(30 14) rotate(13) scale(27 10)">
+      <stop stop-color="#C8D7FF" stop-opacity="0.4"/>
+      <stop offset="1" stop-color="#8C8EF2" stop-opacity="0"/>
+    </radialGradient>
+    <filter id="soft" x="-8" y="-8" width="80" height="48" filterUnits="userSpaceOnUse" color-interpolation-filters="sRGB">
+      <feGaussianBlur stdDeviation="2.5"/>
+    </filter>
+  </defs>
+
+  <g transform="translate(64 0) scale(-1 1)" filter="url(#soft)">
+    <path d="M7 23.5C7 18.9 10.8 15.2 15.5 15.2C16.9 10.7 21.1 7.5 26.1 7.5C31 7.5 35.2 10.5 36.7 14.8C38.5 13.2 40.9 12.2 43.5 12.2C49.1 12.2 53.7 16.4 54.1 21.8C57 22.2 59.2 24 60 26.5H8.2C7.4 25.7 7 24.7 7 23.5Z" fill="url(#cloud)"/>
+    <path d="M11 22.9C12.7 19.8 16 18 19.5 18.5C21 13.4 25.6 10 30.8 10.6C35 11 38.3 13.9 39.4 17.7C43.8 15.5 49 17.3 51.1 21.7C46.2 20.3 41.9 21 37.7 22.1C29.6 24.2 21.5 21.3 11 22.9Z" fill="url(#highlight)"/>
+  </g>
+</svg>
diff --git a/assets/nightly/app-icon.icon/Assets/text.svg b/assets/nightly/app-icon.icon/Assets/text.svg
new file mode 100644
index 000000000000..0b1825f2ef47
--- /dev/null
+++ b/assets/nightly/app-icon.icon/Assets/text.svg
@@ -0,0 +1,3 @@
+<svg width="128" height="128" viewBox="0 0 128 128" fill="none" xmlns="http://www.w3.org/2000/svg">
+  <path d="M33.4509 93V47.56H15.5309V37H64.3309V47.56H46.4109V93H33.4509ZM86.7253 93.96C82.832 93.96 78.9653 93.4533 75.1253 92.44C71.2853 91.3733 68.032 89.88 65.3653 87.96L70.4053 78.04C72.5386 79.5867 75.0186 80.8133 77.8453 81.72C80.672 82.6267 83.5253 83.08 86.4053 83.08C89.6586 83.08 92.2186 82.44 94.0853 81.16C95.952 79.88 96.8853 78.12 96.8853 75.88C96.8853 73.7467 96.0586 72.0667 94.4053 70.84C92.752 69.6133 90.0853 69 86.4053 69H80.4853V60.44L96.0853 42.76L97.5253 47.4H68.1653V37H107.365V45.4L91.8453 63.08L85.2853 59.32H89.0453C95.9253 59.32 101.125 60.8667 104.645 63.96C108.165 67.0533 109.925 71.0267 109.925 75.88C109.925 79.0267 109.099 81.9867 107.445 84.76C105.792 87.48 103.259 89.6933 99.8453 91.4C96.432 93.1067 92.0586 93.96 86.7253 93.96Z" fill="white"/>
+</svg>
diff --git a/assets/nightly/app-icon.icon/icon.json b/assets/nightly/app-icon.icon/icon.json
new file mode 100644
index 000000000000..eb48d26b4a52
--- /dev/null
+++ b/assets/nightly/app-icon.icon/icon.json
@@ -0,0 +1,94 @@
+{
+  "fill": {
+    "automatic-gradient": "display-p3:0.00000,0.00000,0.00000,1.00000"
+  },
+  "groups": [
+    {
+      "layers": [
+        {
+          "glass": true,
+          "image-name": "text.svg",
+          "name": "Text",
+          "position": {
+            "scale": 8.5,
+            "translation-in-points": [0, 0]
+          }
+        },
+        {
+          "glass": false,
+          "image-name": "cloud-upper-right.svg",
+          "name": "Cloud Upper Right",
+          "opacity": 1,
+          "position": {
+            "scale": 15,
+            "translation-in-points": [387.9605131881942, -134.30064713259117]
+          }
+        },
+        {
+          "glass": false,
+          "image-name": "cloud-lower-left.svg",
+          "name": "Cloud Lower Left",
+          "position": {
+            "scale": 25,
+            "translation-in-points": [-309.63750000000005, 268.66077693836917]
+          }
+        },
+        {
+          "glass": true,
+          "hidden": false,
+          "image-name": "background.svg",
+          "name": "Background",
+          "position": {
+            "scale": 8.1,
+            "translation-in-points": [0, -2.171875]
+          }
+        }
+      ],
+      "shadow": {
+        "kind": "neutral",
+        "opacity": 0.6
+      },
+      "translucency": {
+        "enabled": true,
+        "value": 0.2
+      }
+    },
+    {
+      "layers": [],
+      "shadow": {
+        "kind": "neutral",
+        "opacity": 0.6
+      },
+      "translucency": {
+        "enabled": true,
+        "value": 0.2
+      }
+    },
+    {
+      "layers": [],
+      "shadow": {
+        "kind": "neutral",
+        "opacity": 0.6
+      },
+      "translucency": {
+        "enabled": true,
+        "value": 0.2
+      }
+    },
+    {
+      "layers": [],
+      "shadow": {
+        "kind": "neutral",
+        "opacity": 0.6
+      },
+      "translucency": {
+        "enabled": true,
+        "value": 0.2
+      }
+    }
+  ],
+  "supported-platforms": {
+    "circles": ["watchOS"],
+    "squares": "shared"
+  }
+}
diff --git a/assets/nightly/blueprint-ios-1024.png b/assets/nightly/blueprint-ios-1024.png
deleted file mode 100644
index b33d6f337b0b..000000000000
Binary files a/assets/nightly/blueprint-ios-1024.png and /dev/null differ
diff --git a/assets/nightly/blueprint-macos-1024.png b/assets/nightly/blueprint-macos-1024.png
deleted file mode 100644
index 8dba03e01fe1..000000000000
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diff --git a/assets/nightly/blueprint-universal-1024.png b/assets/nightly/blueprint-universal-1024.png
deleted file mode 100644
index b33d6f337b0b..000000000000
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diff --git a/assets/nightly/blueprint-web-apple-touch-180.png b/assets/nightly/blueprint-web-apple-touch-180.png
deleted file mode 100644
index e0e1b9659b83..000000000000
Binary files a/assets/nightly/blueprint-web-apple-touch-180.png and /dev/null differ
diff --git a/assets/nightly/blueprint-web-favicon-16x16.png b/assets/nightly/blueprint-web-favicon-16x16.png
deleted file mode 100644
index 673d84599981..000000000000
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diff --git a/assets/nightly/blueprint-web-favicon-32x32.png b/assets/nightly/blueprint-web-favicon-32x32.png
deleted file mode 100644
index 25bcc95d4aaa..000000000000
Binary files a/assets/nightly/blueprint-web-favicon-32x32.png and /dev/null differ
diff --git a/assets/nightly/blueprint-web-favicon.ico b/assets/nightly/blueprint-web-favicon.ico
deleted file mode 100644
index 36975b997827..000000000000
Binary files a/assets/nightly/blueprint-web-favicon.ico and /dev/null differ
diff --git a/assets/nightly/blueprint-windows.ico b/assets/nightly/blueprint-windows.ico
deleted file mode 100644
index 36975b997827..000000000000
Binary files a/assets/nightly/blueprint-windows.ico and /dev/null differ
diff --git a/assets/nightly/nightly-ios-1024.png b/assets/nightly/nightly-ios-1024.png
new file mode 100644
index 000000000000..42ce5589e9ca
Binary files /dev/null and b/assets/nightly/nightly-ios-1024.png differ
diff --git a/assets/nightly/nightly-macos-1024.png b/assets/nightly/nightly-macos-1024.png
new file mode 100644
index 000000000000..1beacd9f34ad
Binary files /dev/null and b/assets/nightly/nightly-macos-1024.png differ
diff --git a/assets/nightly/nightly-universal-1024.png b/assets/nightly/nightly-universal-1024.png
new file mode 100644
index 000000000000..42ce5589e9ca
Binary files /dev/null and b/assets/nightly/nightly-universal-1024.png differ
diff --git a/assets/nightly/nightly-web-apple-touch-180.png b/assets/nightly/nightly-web-apple-touch-180.png
new file mode 100644
index 000000000000..f09a169458ab
Binary files /dev/null and b/assets/nightly/nightly-web-apple-touch-180.png differ
diff --git a/assets/nightly/nightly-web-favicon-16x16.png b/assets/nightly/nightly-web-favicon-16x16.png
new file mode 100644
index 000000000000..20208f5f3695
Binary files /dev/null and b/assets/nightly/nightly-web-favicon-16x16.png differ
diff --git a/assets/nightly/nightly-web-favicon-32x32.png b/assets/nightly/nightly-web-favicon-32x32.png
new file mode 100644
index 000000000000..b9008d518bce
Binary files /dev/null and b/assets/nightly/nightly-web-favicon-32x32.png differ
diff --git a/assets/nightly/nightly-web-favicon.ico b/assets/nightly/nightly-web-favicon.ico
new file mode 100644
index 000000000000..b6a0b43b93d2
Binary files /dev/null and b/assets/nightly/nightly-web-favicon.ico differ
diff --git a/assets/nightly/nightly-windows.ico b/assets/nightly/nightly-windows.ico
new file mode 100644
index 000000000000..b6a0b43b93d2
Binary files /dev/null and b/assets/nightly/nightly-windows.ico differ
diff --git a/apps/mobile/assets/icon-composer-dev.icon/Assets/T3.svg b/assets/prod/app-icon.icon/Assets/text.svg
similarity index 100%
rename from apps/mobile/assets/icon-composer-dev.icon/Assets/T3.svg
rename to assets/prod/app-icon.icon/Assets/text.svg
diff --git a/apps/mobile/assets/icon-composer-prod.icon/icon.json b/assets/prod/app-icon.icon/icon.json
similarity index 88%
rename from apps/mobile/assets/icon-composer-prod.icon/icon.json
rename to assets/prod/app-icon.icon/icon.json
index 8f7579311f26..8c12c022ef86 100644
--- a/apps/mobile/assets/icon-composer-prod.icon/icon.json
+++ b/assets/prod/app-icon.icon/icon.json
@@ -6,8 +6,8 @@
     {
       "layers": [
         {
-          "image-name": "T3.svg",
-          "name": "T3",
+          "image-name": "text.svg",
+          "name": "Text",
           "position": {
             "scale": 10,
             "translation-in-points": [0, 0]
diff --git a/assets/prod/black-ios-1024.png b/assets/prod/black-ios-1024.png
index 073ad811c250..a8a458337ab0 100644
Binary files a/assets/prod/black-ios-1024.png and b/assets/prod/black-ios-1024.png differ
diff --git a/assets/prod/black-macos-1024.png b/assets/prod/black-macos-1024.png
index 073ad811c250..f5b68b1a6d40 100644
Binary files a/assets/prod/black-macos-1024.png and b/assets/prod/black-macos-1024.png differ
diff --git a/assets/prod/black-universal-1024.png b/assets/prod/black-universal-1024.png
index 073ad811c250..a8a458337ab0 100644
Binary files a/assets/prod/black-universal-1024.png and b/assets/prod/black-universal-1024.png differ
diff --git a/assets/prod/t3-black-web-apple-touch-180.png b/assets/prod/t3-black-web-apple-touch-180.png
index 3ed96e897f33..2e30aecbc72b 100644
Binary files a/assets/prod/t3-black-web-apple-touch-180.png and b/assets/prod/t3-black-web-apple-touch-180.png differ
diff --git a/assets/prod/t3-black-web-favicon-16x16.png b/assets/prod/t3-black-web-favicon-16x16.png
index 44c99d844718..c175f2c87a21 100644
Binary files a/assets/prod/t3-black-web-favicon-16x16.png and b/assets/prod/t3-black-web-favicon-16x16.png differ
diff --git a/assets/prod/t3-black-web-favicon-32x32.png b/assets/prod/t3-black-web-favicon-32x32.png
index c0ed3eddf734..fe6fb545b859 100644
Binary files a/assets/prod/t3-black-web-favicon-32x32.png and b/assets/prod/t3-black-web-favicon-32x32.png differ
diff --git a/assets/prod/t3-black-web-favicon.ico b/assets/prod/t3-black-web-favicon.ico
index 947f6d57b92a..a0fe86da92f0 100644
Binary files a/assets/prod/t3-black-web-favicon.ico and b/assets/prod/t3-black-web-favicon.ico differ
diff --git a/assets/prod/t3-black-windows.ico b/assets/prod/t3-black-windows.ico
index e3ab4ae5e024..a0fe86da92f0 100644
Binary files a/assets/prod/t3-black-windows.ico and b/assets/prod/t3-black-windows.ico differ
diff --git a/docs/reference/scripts.md b/docs/reference/scripts.md
index d4d2b96869ee..6bdea2666652 100644
--- a/docs/reference/scripts.md
+++ b/docs/reference/scripts.md
@@ -1,29 +1,29 @@
 # Scripts
 
-- `bun run dev` — Starts contracts, server, and web in `turbo watch` mode.
-- `bun run dev:server` — Starts just the WebSocket server (uses Bun TypeScript execution).
-- `bun run dev:web` — Starts just the Vite dev server for the web app.
-- Dev commands default `T3CODE_STATE_DIR` to `~/.t3/dev` to keep dev state isolated from desktop/prod state.
+- `vp run dev` — Starts contracts, server, and web in watch mode.
+- `vp run dev:server` — Starts just the WebSocket server. The server process runs on Bun (`@effect/platform-bun` + `BunPtyAdapter`), but task running uses `vp run`.
+- `vp run dev:web` — Starts just the Vite dev server for the web app.
+- Dev commands default `T3CODE_HOME` to `~/.t3` — the same shared home the desktop/production app uses. Override with `--home-dir` (see below) to keep dev state separate.
 - Override server CLI-equivalent flags from root dev commands with `--`, for example:
-  `bun run dev -- --base-dir ~/.t3-2`
-- `bun run start` — Runs the production server (serves built web app as static files).
-- `bun run build` — Builds contracts, web app, and server through Turbo.
-- `bun run typecheck` — Strict TypeScript checks for all packages.
-- `bun run test` — Runs workspace tests.
-- `bun run dist:desktop:artifact -- --platform <mac|linux|win> --target <target> --arch <arch>` — Builds a desktop artifact for a specific platform/target/arch.
-- `bun run dist:desktop:dmg` — Builds a shareable macOS `.dmg` into `./release`.
-- `bun run dist:desktop:dmg:x64` — Builds an Intel macOS `.dmg`.
-- `bun run dist:desktop:linux` — Builds a Linux AppImage into `./release`.
-- `bun run dist:desktop:win` — Builds a Windows NSIS installer into `./release`.
+  `vp run dev -- --home-dir ~/.t3-2`
+- `vp run start` — Runs the production server (serves built web app as static files).
+- `vp run build` — Builds contracts, web app, and server.
+- `vp run typecheck` — Strict TypeScript checks for all packages.
+- `vp run test` — Runs workspace tests.
+- `vp run dist:desktop:artifact -- --platform <mac|linux|win> --target <target> --arch <arch>` — Builds a desktop artifact for a specific platform/target/arch.
+- `vp run dist:desktop:dmg` — Builds a shareable macOS `.dmg` into `./release`.
+- `vp run dist:desktop:dmg:x64` — Builds an Intel macOS `.dmg`.
+- `vp run dist:desktop:linux` — Builds a Linux AppImage into `./release`.
+- `vp run dist:desktop:win` — Builds a Windows NSIS installer into `./release`.
 
 ## Desktop `.dmg` packaging notes
 
 - Default build is unsigned/not notarized for local sharing.
-- The DMG build uses `assets/macos-icon-1024.png` as the production app icon source.
+- The DMG build uses `assets/prod/black-macos-1024.png` as the production app icon source.
 - Desktop production windows load the bundled UI from `t3code://app/index.html` (not a `127.0.0.1` document URL).
 - Desktop packaging includes `apps/server/dist` (the `t3` backend) and starts it on loopback with an auth token for WebSocket/API traffic.
 - Your tester can still open it on macOS by right-clicking the app and choosing **Open** on first launch.
-- To keep staging files for debugging package contents, run: `bun run dist:desktop:dmg -- --keep-stage`
+- To keep staging files for debugging package contents, run: `vp run dist:desktop:dmg -- --keep-stage`
 - To allow code-signing/notarization when configured in CI/secrets, add: `--signed`.
 - Signed macOS builds also require `T3CODE_APPLE_TEAM_ID` and
   `T3CODE_MACOS_PROVISIONING_PROFILE`. The passkey RP domain is derived from
@@ -38,8 +38,8 @@
 
 Set `T3CODE_DEV_INSTANCE` to any value to deterministically shift all dev ports together.
 
-- Default ports: server `3773`, web `5733`
+- Default ports: server `13773`, web `5733`
 - Shifted ports: `base + offset` (offset is hashed from `T3CODE_DEV_INSTANCE`)
-- Example: `T3CODE_DEV_INSTANCE=branch-a bun run dev:desktop`
+- Example: `T3CODE_DEV_INSTANCE=branch-a vp run dev:desktop`
 
 If you want full control instead of hashing, set `T3CODE_PORT_OFFSET` to a numeric offset.
diff --git a/package.json b/package.json
index 4464d49f159a..600c3083a8db 100644
--- a/package.json
+++ b/package.json
@@ -14,6 +14,8 @@
     "start:marketing": "vp run --filter @t3tools/marketing preview",
     "start:mock-update-server": "node scripts/mock-update-server.ts",
     "screenshots:mobile": "node scripts/mobile-showcase.ts",
+    "icons:export": "node scripts/export-brand-icons.ts",
+    "icons:check": "node scripts/export-brand-icons.ts --check",
     "build": "vp run --filter './apps/*' --filter './packages/*' --filter './oxlint-plugin-t3code' --filter './scripts' build",
     "sync:upstream-prs": "node scripts/sync-upstream-pr-tracks.mjs",
     "build:marketing": "vp run --filter @t3tools/marketing build",
diff --git a/packages/client-runtime/src/state/threadSort.test.ts b/packages/client-runtime/src/state/threadSort.test.ts
new file mode 100644
index 000000000000..dd6f8c3a295e
--- /dev/null
+++ b/packages/client-runtime/src/state/threadSort.test.ts
@@ -0,0 +1,71 @@
+import { describe, expect, it } from "vite-plus/test";
+
+import { sortThreads, type ThreadSortInput } from "./threadSort.ts";
+
+type TestThread = { readonly id: string } & ThreadSortInput;
+
+function makeThread(overrides: Partial<TestThread> = {}): TestThread {
+  return {
+    id: "thread-1",
+    createdAt: "2026-03-09T10:00:00.000Z",
+    updatedAt: "2026-03-09T10:00:00.000Z",
+    messages: [],
+    latestUserMessageAt: null,
+    ...overrides,
+  };
+}
+
+describe("sortThreads", () => {
+  it("falls back to updatedAt and createdAt when latestUserMessageAt is invalid and there are no messages", () => {
+    const sorted = sortThreads(
+      [
+        makeThread({
+          id: "thread-1",
+          latestUserMessageAt: "not-a-date",
+          createdAt: "2026-03-09T10:00:00.000Z",
+          updatedAt: "2026-03-09T10:05:00.000Z",
+        }),
+        makeThread({
+          id: "thread-2",
+          latestUserMessageAt: "still-not-a-date",
+          createdAt: "invalid-created-at",
+          updatedAt: "invalid-updated-at",
+        }),
+        makeThread({
+          id: "thread-3",
+          latestUserMessageAt: "invalid-latest-user-message-at",
+          createdAt: "2026-03-09T10:06:00.000Z",
+          updatedAt: "invalid-updated-at",
+        }),
+      ],
+      "updated_at",
+    );
+
+    expect(sorted.map((thread) => thread.id)).toEqual(["thread-3", "thread-1", "thread-2"]);
+  });
+
+  it("falls back to the latest valid user message when latestUserMessageAt is invalid", () => {
+    const sorted = sortThreads(
+      [
+        makeThread({
+          id: "thread-1",
+          latestUserMessageAt: "invalid-latest-user-message-at",
+          updatedAt: "2026-03-09T10:00:00.000Z",
+          messages: [
+            { role: "user", createdAt: "2026-03-09T10:05:00.000Z" },
+            { role: "assistant", createdAt: "2026-03-09T10:30:00.000Z" },
+            { role: "user", createdAt: "2026-03-09T10:20:00.000Z" },
+          ],
+        }),
+        makeThread({
+          id: "thread-2",
+          createdAt: "2026-03-09T10:15:00.000Z",
+          updatedAt: "2026-03-09T10:15:00.000Z",
+        }),
+      ],
+      "updated_at",
+    );
+
+    expect(sorted.map((thread) => thread.id)).toEqual(["thread-1", "thread-2"]);
+  });
+});
diff --git a/packages/client-runtime/src/state/threadSort.ts b/packages/client-runtime/src/state/threadSort.ts
index 4da184962e61..aed63cd442d7 100644
--- a/packages/client-runtime/src/state/threadSort.ts
+++ b/packages/client-runtime/src/state/threadSort.ts
@@ -32,7 +32,10 @@ function getFirstSortableTimestamp(...values: Array<string | null | undefined>):
 
 function getLatestUserMessageTimestamp(thread: ThreadSortInput): number {
   if (thread.latestUserMessageAt) {
-    return toSortableTimestamp(thread.latestUserMessageAt) ?? Number.NEGATIVE_INFINITY;
+    const latestUserMessageTimestamp = toSortableTimestamp(thread.latestUserMessageAt);
+    if (latestUserMessageTimestamp !== null) {
+      return latestUserMessageTimestamp;
+    }
   }
 
   let latestUserMessageTimestamp: number | null = null;
diff --git a/packages/contracts/src/ipc.ts b/packages/contracts/src/ipc.ts
index 42e32e27121c..a0a857a6f35d 100644
--- a/packages/contracts/src/ipc.ts
+++ b/packages/contracts/src/ipc.ts
@@ -213,6 +213,7 @@ export interface DesktopUpdateState {
   runningUnderArm64Translation: boolean;
   availableVersion: string | null;
   downloadedVersion: string | null;
+  releaseNotes: ReadonlyArray<DesktopUpdateReleaseNote>;
   downloadPercent: number | null;
   checkedAt: string | null;
   message: string | null;
@@ -220,6 +221,16 @@ export interface DesktopUpdateState {
   canRetry: boolean;
 }
 
+export interface DesktopUpdateReleaseNote {
+  version: string;
+  items: ReadonlyArray<string>;
+}
+
+export const DesktopUpdateReleaseNoteSchema = Schema.Struct({
+  version: Schema.String,
+  items: Schema.Array(Schema.String),
+});
+
 export const DesktopUpdateStateSchema = Schema.Struct({
   enabled: Schema.Boolean,
   status: DesktopUpdateStatusSchema,
@@ -230,6 +241,7 @@ export const DesktopUpdateStateSchema = Schema.Struct({
   runningUnderArm64Translation: Schema.Boolean,
   availableVersion: Schema.NullOr(Schema.String),
   downloadedVersion: Schema.NullOr(Schema.String),
+  releaseNotes: Schema.Array(DesktopUpdateReleaseNoteSchema),
   downloadPercent: Schema.NullOr(Schema.Number),
   checkedAt: Schema.NullOr(Schema.String),
   message: Schema.NullOr(Schema.String),
diff --git a/packages/contracts/src/settings.ts b/packages/contracts/src/settings.ts
index c1bb0423f4bb..9a1d10563d5a 100644
--- a/packages/contracts/src/settings.ts
+++ b/packages/contracts/src/settings.ts
@@ -252,7 +252,7 @@ export const CursorSettings = makeProviderSettingsSchema(
       Schema.withDecodingDefault(Effect.succeed(false)),
       Schema.annotateKey({ providerSettingsForm: { hidden: true } }),
     ),
-    binaryPath: makeBinaryPathSetting("agent").pipe(
+    binaryPath: makeBinaryPathSetting("cursor-agent").pipe(
       Schema.annotateKey({
         title: "Legacy binary path",
         description: "Legacy Cursor ACP setting. Cursor now runs through @cursor/sdk.",
diff --git a/packages/shared/src/remote.test.ts b/packages/shared/src/remote.test.ts
index 24e787570099..5b7a9973652a 100644
--- a/packages/shared/src/remote.test.ts
+++ b/packages/shared/src/remote.test.ts
@@ -59,6 +59,70 @@ describe("remote", () => {
     });
   });
 
+  it("treats a protocol-relative host as https", () => {
+    expect(
+      resolveRemotePairingTarget({
+        host: "//remote.example.com",
+        pairingCode: "pairing-token",
+      }),
+    ).toEqual({
+      credential: "pairing-token",
+      httpBaseUrl: "https://remote.example.com/",
+      wsBaseUrl: "wss://remote.example.com/",
+    });
+  });
+
+  it("preserves the port when normalizing a protocol-relative host", () => {
+    expect(
+      resolveRemotePairingTarget({
+        host: "//remote.example.com:3000",
+        pairingCode: "pairing-token",
+      }),
+    ).toEqual({
+      credential: "pairing-token",
+      httpBaseUrl: "https://remote.example.com:3000/",
+      wsBaseUrl: "wss://remote.example.com:3000/",
+    });
+  });
+
+  it("normalizes a protocol-relative host from a hosted pairing link", () => {
+    expect(
+      resolveRemotePairingTarget({
+        pairingUrl: "https://app.t3.codes/pair?host=%2F%2Fremote.example.com#token=pairing-token",
+      }),
+    ).toEqual({
+      credential: "pairing-token",
+      httpBaseUrl: "https://remote.example.com/",
+      wsBaseUrl: "wss://remote.example.com/",
+    });
+  });
+
+  it("collapses extra leading slashes instead of producing an empty host", () => {
+    expect(
+      resolveRemotePairingTarget({
+        host: "///example.com",
+        pairingCode: "pairing-token",
+      }),
+    ).toEqual({
+      credential: "pairing-token",
+      httpBaseUrl: "https://example.com/",
+      wsBaseUrl: "wss://example.com/",
+    });
+  });
+
+  it("does not double-prepend https when the host already carries a scheme", () => {
+    expect(
+      resolveRemotePairingTarget({
+        host: "//https://example.com",
+        pairingCode: "pairing-token",
+      }),
+    ).toEqual({
+      credential: "pairing-token",
+      httpBaseUrl: "https://example.com/",
+      wsBaseUrl: "wss://example.com/",
+    });
+  });
+
   it("preserves host ports when normalizing a bare host input", () => {
     expect(
       resolveRemotePairingTarget({
diff --git a/packages/shared/src/remote.ts b/packages/shared/src/remote.ts
index 7347dbc74a17..0adfc6fe90a6 100644
--- a/packages/shared/src/remote.ts
+++ b/packages/shared/src/remote.ts
@@ -81,10 +81,10 @@ const normalizeRemoteBaseUrl = (
     throw new RemoteBackendUrlMissingError();
   }
 
-  const normalizedInput =
-    /^[a-zA-Z][a-zA-Z\d+-]*:\/\//.test(trimmed) || trimmed.startsWith("//")
-      ? trimmed
-      : `https://${trimmed}`;
+  const withoutLeadingSlashes = trimmed.replace(/^\/+/, "");
+  const normalizedInput = /^[a-zA-Z][a-zA-Z\d+-]*:\/\//.test(withoutLeadingSlashes)
+    ? withoutLeadingSlashes
+    : `https://${withoutLeadingSlashes}`;
   let url: URL;
   try {
     url = new URL(normalizedInput);
diff --git a/scripts/export-brand-icons.ts b/scripts/export-brand-icons.ts
new file mode 100644
index 000000000000..c24169dc2e13
--- /dev/null
+++ b/scripts/export-brand-icons.ts
@@ -0,0 +1,800 @@
+#!/usr/bin/env node
+
+import * as NodeRuntime from "@effect/platform-node/NodeRuntime";
+import * as NodeServices from "@effect/platform-node/NodeServices";
+import { HostProcessEnvironment } from "@t3tools/shared/hostProcess";
+import * as Console from "effect/Console";
+import * as Effect from "effect/Effect";
+import * as FileSystem from "effect/FileSystem";
+import * as Option from "effect/Option";
+import * as Path from "effect/Path";
+import * as Schema from "effect/Schema";
+import * as Stream from "effect/Stream";
+import { Command, Flag } from "effect/unstable/cli";
+import { ChildProcess, ChildProcessSpawner } from "effect/unstable/process";
+
+import { BRAND_ASSET_PATHS } from "./lib/brand-assets.ts";
+import { encodePngIco, readPngDimensions, WINDOWS_ICON_SIZES } from "./lib/icon-export.ts";
+
+const DESIGN_GENERATION = 26;
+const ICON_COMPOSER_EXECUTABLE_PARTS = [
+  "Contents",
+  "Applications",
+  "Icon Composer.app",
+  "Contents",
+  "Executables",
+  "ictool",
+] as const;
+const STANDALONE_ICON_COMPOSER_EXECUTABLE_PARTS = [
+  "Icon Composer.app",
+  "Contents",
+  "Executables",
+  "ictool",
+] as const;
+const NonNegativeInt = Schema.Int.check(Schema.isGreaterThanOrEqualTo(0));
+
+const IconComposerVersion = Schema.Struct({
+  "bundle-version": Schema.NonEmptyString,
+  "short-bundle-version": Schema.NonEmptyString,
+});
+const decodeIconComposerVersion = Schema.decodeUnknownEffect(
+  Schema.fromJsonString(IconComposerVersion),
+);
+
+type IconPlatform = "iOS";
+
+interface VariantOutputs {
+  readonly ios: string;
+  readonly macos: string;
+  readonly universal: string;
+  readonly appleTouch: string;
+  readonly favicon16: string;
+  readonly favicon32: string;
+  readonly faviconIco: string;
+  readonly windowsIco: string;
+}
+
+interface IconVariant {
+  readonly label: string;
+  readonly source: string;
+  readonly outputs: VariantOutputs;
+}
+
+interface IconComposerTool {
+  readonly path: string;
+  readonly version: string;
+  readonly bundleVersion: string;
+  readonly supportsDesignGeneration: boolean;
+}
+
+interface CommandResult {
+  readonly stdout: string;
+  readonly stderr: string;
+  readonly exitCode: number;
+}
+
+export class IconExportFileSystemError extends Schema.TaggedErrorClass<IconExportFileSystemError>()(
+  "IconExportFileSystemError",
+  {
+    operation: Schema.Literals([
+      "resolve-repository-root",
+      "check-path",
+      "read-directory",
+      "read-file",
+      "make-directory",
+      "make-temp-directory",
+      "make-temp-file",
+      "write-file",
+      "rename-file",
+    ]),
+    path: Schema.String,
+    cause: Schema.Defect(),
+  },
+) {
+  override get message(): string {
+    return `Icon export file-system operation '${this.operation}' failed for ${this.path}.`;
+  }
+}
+
+export class IconExportProcessError extends Schema.TaggedErrorClass<IconExportProcessError>()(
+  "IconExportProcessError",
+  {
+    operation: Schema.Literals(["spawn", "collect-stdout", "collect-stderr", "wait-for-exit"]),
+    command: Schema.String,
+    argumentCount: NonNegativeInt,
+    cause: Schema.Defect(),
+  },
+) {
+  override get message(): string {
+    return `Icon export process operation '${this.operation}' failed for ${this.command}.`;
+  }
+}
+
+export class IconExportCommandFailedError extends Schema.TaggedErrorClass<IconExportCommandFailedError>()(
+  "IconExportCommandFailedError",
+  {
+    command: Schema.String,
+    argumentCount: NonNegativeInt,
+    exitCode: Schema.Int,
+    sourcePath: Schema.String,
+    size: Schema.Int,
+    stdout: Schema.optional(Schema.String),
+    stderr: Schema.optional(Schema.String),
+  },
+) {
+  override get message(): string {
+    return `Icon Composer failed to export ${this.sourcePath} at ${this.size}x${this.size}.`;
+  }
+}
+
+export class IconExportToolResolutionError extends Schema.TaggedErrorClass<IconExportToolResolutionError>()(
+  "IconExportToolResolutionError",
+  {
+    reason: Schema.Literals(["configured-invalid", "configured-outdated", "not-found"]),
+    designGeneration: Schema.Int,
+    toolPath: Schema.optional(Schema.String),
+    version: Schema.optional(Schema.String),
+  },
+) {
+  override get message(): string {
+    switch (this.reason) {
+      case "configured-invalid":
+        return `ICON_COMPOSER_TOOL does not point to Icon Composer's export-capable ictool: ${this.toolPath}`;
+      case "configured-outdated":
+        return `ICON_COMPOSER_TOOL points to Icon Composer ${this.version}, but version 2 or newer is required for design generation ${this.designGeneration}.`;
+      case "not-found":
+        return `Could not find an Icon Composer 2.x exporter compatible with design generation ${this.designGeneration}. Install a compatible Icon Composer/Xcode or set ICON_COMPOSER_TOOL to Icon Composer.app/Contents/Executables/ictool.`;
+    }
+  }
+}
+
+export class IconExportSourceMissingError extends Schema.TaggedErrorClass<IconExportSourceMissingError>()(
+  "IconExportSourceMissingError",
+  {
+    sourcePath: Schema.String,
+  },
+) {
+  override get message(): string {
+    return `Missing Icon Composer source project: ${this.sourcePath}`;
+  }
+}
+
+export class IconExportRenditionError extends Schema.TaggedErrorClass<IconExportRenditionError>()(
+  "IconExportRenditionError",
+  {
+    sourcePath: Schema.String,
+    outputPath: Schema.String,
+    expectedSize: Schema.Int,
+    actualWidth: Schema.optional(Schema.Int),
+    actualHeight: Schema.optional(Schema.Int),
+    cause: Schema.optional(Schema.Defect()),
+  },
+) {
+  override get message(): string {
+    const actual =
+      this.actualWidth === undefined || this.actualHeight === undefined
+        ? "an invalid PNG"
+        : `${this.actualWidth}x${this.actualHeight}`;
+    return `Icon Composer produced ${actual}; expected ${this.expectedSize}x${this.expectedSize} for ${this.sourcePath}.`;
+  }
+}
+
+export class IconExportEncodingError extends Schema.TaggedErrorClass<IconExportEncodingError>()(
+  "IconExportEncodingError",
+  {
+    variant: Schema.String,
+    cause: Schema.Defect(),
+  },
+) {
+  override get message(): string {
+    return `Failed to encode ICO renditions for the ${this.variant} icon.`;
+  }
+}
+
+export class IconExportAssetsStaleError extends Schema.TaggedErrorClass<IconExportAssetsStaleError>()(
+  "IconExportAssetsStaleError",
+  {
+    paths: Schema.Array(Schema.String),
+  },
+) {
+  override get message(): string {
+    return `Generated icon assets are stale:\n${this.paths.map((path) => `- ${path}`).join("\n")}`;
+  }
+}
+
+const ICON_VARIANTS = [
+  {
+    label: "development",
+    source: BRAND_ASSET_PATHS.developmentIconComposerProject,
+    outputs: {
+      ios: BRAND_ASSET_PATHS.developmentIosIconPng,
+      macos: BRAND_ASSET_PATHS.developmentDesktopIconPng,
+      universal: BRAND_ASSET_PATHS.developmentUniversalIconPng,
+      appleTouch: BRAND_ASSET_PATHS.developmentWebAppleTouchIconPng,
+      favicon16: BRAND_ASSET_PATHS.developmentWebFavicon16Png,
+      favicon32: BRAND_ASSET_PATHS.developmentWebFavicon32Png,
+      faviconIco: BRAND_ASSET_PATHS.developmentWebFaviconIco,
+      windowsIco: BRAND_ASSET_PATHS.developmentWindowsIconIco,
+    },
+  },
+  {
+    label: "preview",
+    source: BRAND_ASSET_PATHS.nightlyIconComposerProject,
+    outputs: {
+      ios: BRAND_ASSET_PATHS.nightlyIosIconPng,
+      macos: BRAND_ASSET_PATHS.nightlyMacIconPng,
+      universal: BRAND_ASSET_PATHS.nightlyLinuxIconPng,
+      appleTouch: BRAND_ASSET_PATHS.nightlyWebAppleTouchIconPng,
+      favicon16: BRAND_ASSET_PATHS.nightlyWebFavicon16Png,
+      favicon32: BRAND_ASSET_PATHS.nightlyWebFavicon32Png,
+      faviconIco: BRAND_ASSET_PATHS.nightlyWebFaviconIco,
+      windowsIco: BRAND_ASSET_PATHS.nightlyWindowsIconIco,
+    },
+  },
+  {
+    label: "production",
+    source: BRAND_ASSET_PATHS.productionIconComposerProject,
+    outputs: {
+      ios: BRAND_ASSET_PATHS.productionIosIconPng,
+      macos: BRAND_ASSET_PATHS.productionMacIconPng,
+      universal: BRAND_ASSET_PATHS.productionLinuxIconPng,
+      appleTouch: BRAND_ASSET_PATHS.productionWebAppleTouchIconPng,
+      favicon16: BRAND_ASSET_PATHS.productionWebFavicon16Png,
+      favicon32: BRAND_ASSET_PATHS.productionWebFavicon32Png,
+      faviconIco: BRAND_ASSET_PATHS.productionWebFaviconIco,
+      windowsIco: BRAND_ASSET_PATHS.productionWindowsIconIco,
+    },
+  },
+] as const satisfies ReadonlyArray<IconVariant>;
+
+const MACOS_EXPORT_CODEX_PROMPT = [
+  "Use [@Computer](plugin://computer-use@openai-bundled) and the Icon Composer app to export the three macOS app icons in this repository.",
+  "For each project below, use Platform: macOS pre-Tahoe, Appearance: Default, Size: 1024pt, and Scale: 1×, then save the PNG to the exact destination:",
+  ...ICON_VARIANTS.map((variant) => `- ${variant.source} -> ${variant.outputs.macos}`),
+  "Do not resize, composite, or otherwise post-process the exported PNGs.",
+  "Verify every result is 1024×1024 and has the classic macOS safe area: an 824×824 opaque body inset 100px on every side, with only Icon Composer's native shadow extending beyond it.",
+];
+
+const RepositoryRoot = Effect.service(Path.Path).pipe(
+  Effect.flatMap((path) => path.fromFileUrl(new URL("..", import.meta.url))),
+  Effect.mapError(
+    (cause) =>
+      new IconExportFileSystemError({
+        operation: "resolve-repository-root",
+        path: new URL("..", import.meta.url).pathname,
+        cause,
+      }),
+  ),
+);
+
+const collectStreamAsString = <E>(stream: Stream.Stream<Uint8Array, E>) =>
+  stream.pipe(
+    Stream.decodeText(),
+    Stream.runFold(
+      () => "",
+      (acc, chunk) => acc + chunk,
+    ),
+  );
+
+const runCommand = Effect.fn("iconExport.runCommand")(function* (
+  command: string,
+  args: ReadonlyArray<string>,
+) {
+  const spawner = yield* ChildProcessSpawner.ChildProcessSpawner;
+  const child = yield* spawner.spawn(ChildProcess.make(command, args)).pipe(
+    Effect.mapError(
+      (cause) =>
+        new IconExportProcessError({
+          operation: "spawn",
+          command,
+          argumentCount: args.length,
+          cause,
+        }),
+    ),
+  );
+  const [stdout, stderr, exitCode] = yield* Effect.all(
+    [
+      collectStreamAsString(child.stdout).pipe(
+        Effect.mapError(
+          (cause) =>
+            new IconExportProcessError({
+              operation: "collect-stdout",
+              command,
+              argumentCount: args.length,
+              cause,
+            }),
+        ),
+      ),
+      collectStreamAsString(child.stderr).pipe(
+        Effect.mapError(
+          (cause) =>
+            new IconExportProcessError({
+              operation: "collect-stderr",
+              command,
+              argumentCount: args.length,
+              cause,
+            }),
+        ),
+      ),
+      child.exitCode.pipe(
+        Effect.map(Number),
+        Effect.mapError(
+          (cause) =>
+            new IconExportProcessError({
+              operation: "wait-for-exit",
+              command,
+              argumentCount: args.length,
+              cause,
+            }),
+        ),
+      ),
+    ],
+    { concurrency: "unbounded" },
+  );
+
+  return { stdout, stderr, exitCode } satisfies CommandResult;
+});
+
+const iconComposerToolFromDeveloperDirectory = (developerDirectory: string, path: Path.Path) =>
+  path.resolve(developerDirectory, "..", ...ICON_COMPOSER_EXECUTABLE_PARTS.slice(1));
+
+const readSelectedDeveloperDirectory = Effect.fn("iconExport.readSelectedDeveloperDirectory")(
+  function* () {
+    const result = yield* runCommand("xcode-select", ["-p"]).pipe(Effect.option);
+    return Option.flatMap(result, (output) => {
+      const developerDirectory = output.stdout.trim();
+      return output.exitCode === 0 && developerDirectory.length > 0
+        ? Option.some(developerDirectory)
+        : Option.none();
+    });
+  },
+);
+
+const findXcodeAppCandidates = Effect.fn("iconExport.findXcodeAppCandidates")(function* (
+  directory: string,
+) {
+  const fs = yield* FileSystem.FileSystem;
+  const path = yield* Path.Path;
+  const entries = yield* fs.readDirectory(directory).pipe(
+    Effect.mapError(
+      (cause) =>
+        new IconExportFileSystemError({
+          operation: "read-directory",
+          path: directory,
+          cause,
+        }),
+    ),
+    Effect.orElseSucceed(() => []),
+  );
+  return entries
+    .filter((entry) => /^Xcode.*\.app$/.test(entry))
+    .map((entry) => path.join(directory, entry, ...ICON_COMPOSER_EXECUTABLE_PARTS));
+});
+
+const probeIconComposerTool = Effect.fn("iconExport.probeIconComposerTool")(function* (
+  candidate: string,
+) {
+  const fs = yield* FileSystem.FileSystem;
+  const exists = yield* fs.exists(candidate).pipe(
+    Effect.mapError(
+      (cause) =>
+        new IconExportFileSystemError({
+          operation: "check-path",
+          path: candidate,
+          cause,
+        }),
+    ),
+    Effect.orElseSucceed(() => false),
+  );
+  if (!exists) return Option.none<IconComposerTool>();
+
+  const result = yield* runCommand(candidate, ["--version"]).pipe(Effect.option);
+  if (Option.isNone(result) || result.value.exitCode !== 0) {
+    return Option.none<IconComposerTool>();
+  }
+
+  const version = yield* decodeIconComposerVersion(result.value.stdout).pipe(Effect.option);
+  if (Option.isNone(version)) return Option.none<IconComposerTool>();
+
+  const bundleVersion = version.value["bundle-version"];
+  const shortVersion = version.value["short-bundle-version"];
+  return Option.some({
+    path: candidate,
+    version: `${shortVersion} (${bundleVersion})`,
+    bundleVersion,
+    supportsDesignGeneration: Number.parseInt(shortVersion, 10) >= 2,
+  });
+});
+
+const resolveIconComposerTool = Effect.fn("iconExport.resolveIconComposerTool")(function* () {
+  const path = yield* Path.Path;
+  const environment = yield* HostProcessEnvironment;
+  const configuredTool = environment.ICON_COMPOSER_TOOL?.trim();
+  if (configuredTool) {
+    const tool = yield* probeIconComposerTool(configuredTool);
+    if (Option.isNone(tool)) {
+      return yield* new IconExportToolResolutionError({
+        reason: "configured-invalid",
+        designGeneration: DESIGN_GENERATION,
+        toolPath: configuredTool,
+      });
+    }
+    if (!tool.value.supportsDesignGeneration) {
+      return yield* new IconExportToolResolutionError({
+        reason: "configured-outdated",
+        designGeneration: DESIGN_GENERATION,
+        toolPath: configuredTool,
+        version: tool.value.version,
+      });
+    }
+    return tool.value;
+  }
+
+  const selectedDeveloperDirectory = yield* readSelectedDeveloperDirectory();
+  const configuredDeveloperDirectory = environment.DEVELOPER_DIR?.trim();
+  const homeDirectory = environment.HOME?.trim();
+  const searchDirectories = [
+    "/Applications",
+    ...(homeDirectory ? [path.join(homeDirectory, "Downloads")] : []),
+  ];
+  const xcodeCandidates = yield* Effect.forEach(searchDirectories, findXcodeAppCandidates, {
+    concurrency: "unbounded",
+  });
+  const candidates = new Set<string>([
+    ...(configuredDeveloperDirectory
+      ? [iconComposerToolFromDeveloperDirectory(configuredDeveloperDirectory, path)]
+      : []),
+    ...Option.match(selectedDeveloperDirectory, {
+      onNone: () => [],
+      onSome: (developerDirectory) => [
+        iconComposerToolFromDeveloperDirectory(developerDirectory, path),
+      ],
+    }),
+    path.join("/Applications", ...STANDALONE_ICON_COMPOSER_EXECUTABLE_PARTS),
+    ...(homeDirectory
+      ? [path.join(homeDirectory, "Applications", ...STANDALONE_ICON_COMPOSER_EXECUTABLE_PARTS)]
+      : []),
+    ...xcodeCandidates.flat(),
+  ]);
+  const probed = yield* Effect.forEach([...candidates], probeIconComposerTool, {
+    concurrency: "unbounded",
+  });
+  const compatibleTools = probed
+    .filter(Option.isSome)
+    .map((tool) => tool.value)
+    .filter((tool) => tool.supportsDesignGeneration)
+    .sort((left, right) =>
+      right.bundleVersion.localeCompare(left.bundleVersion, undefined, { numeric: true }),
+    );
+  const newestTool = compatibleTools[0];
+  if (newestTool) return newestTool;
+
+  return yield* new IconExportToolResolutionError({
+    reason: "not-found",
+    designGeneration: DESIGN_GENERATION,
+  });
+});
+
+const renderIcon = Effect.fn("iconExport.renderIcon")(function* (
+  toolPath: string,
+  sourcePath: string,
+  outputPath: string,
+  platform: IconPlatform,
+  size: number,
+) {
+  const fs = yield* FileSystem.FileSystem;
+  const args = [
+    sourcePath,
+    "--export-image",
+    "--output-file",
+    outputPath,
+    "--platform",
+    platform,
+    "--rendition",
+    "Default",
+    "--width",
+    String(size),
+    "--height",
+    String(size),
+    "--scale",
+    "1",
+    "--design-generation",
+    String(DESIGN_GENERATION),
+  ];
+  const result = yield* runCommand(toolPath, args);
+  if (result.exitCode !== 0) {
+    return yield* new IconExportCommandFailedError({
+      command: toolPath,
+      argumentCount: args.length,
+      exitCode: result.exitCode,
+      sourcePath,
+      size,
+      ...(result.stdout.trim() ? { stdout: result.stdout.trim() } : {}),
+      ...(result.stderr.trim() ? { stderr: result.stderr.trim() } : {}),
+    });
+  }
+
+  const contents = yield* fs.readFile(outputPath).pipe(
+    Effect.mapError(
+      (cause) =>
+        new IconExportFileSystemError({
+          operation: "read-file",
+          path: outputPath,
+          cause,
+        }),
+    ),
+  );
+  const buffer = Buffer.from(contents);
+  const dimensions = yield* Effect.try({
+    try: () => readPngDimensions(buffer),
+    catch: (cause) =>
+      new IconExportRenditionError({
+        sourcePath,
+        outputPath,
+        expectedSize: size,
+        cause,
+      }),
+  });
+  if (dimensions.width !== size || dimensions.height !== size) {
+    return yield* new IconExportRenditionError({
+      sourcePath,
+      outputPath,
+      expectedSize: size,
+      actualWidth: dimensions.width,
+      actualHeight: dimensions.height,
+    });
+  }
+  return buffer;
+});
+
+const renderVariant = Effect.fn("iconExport.renderVariant")(function* (
+  toolPath: string,
+  repositoryRoot: string,
+  temporaryDirectory: string,
+  variant: IconVariant,
+) {
+  const fs = yield* FileSystem.FileSystem;
+  const path = yield* Path.Path;
+  const sourcePath = path.join(repositoryRoot, variant.source);
+  const sourceExists = yield* fs.exists(sourcePath).pipe(
+    Effect.mapError(
+      (cause) =>
+        new IconExportFileSystemError({
+          operation: "check-path",
+          path: sourcePath,
+          cause,
+        }),
+    ),
+  );
+  if (!sourceExists) {
+    return yield* new IconExportSourceMissingError({ sourcePath: variant.source });
+  }
+
+  const renditionCache = new Map<string, Buffer>();
+  const render = Effect.fn("iconExport.renderVariant.rendition")(function* (
+    platform: IconPlatform,
+    size: number,
+  ) {
+    const cacheKey = `${platform}-${size}`;
+    const cached = renditionCache.get(cacheKey);
+    if (cached) return cached;
+
+    const outputPath = path.join(temporaryDirectory, `${variant.label}-${platform}-${size}.png`);
+    const contents = yield* renderIcon(toolPath, sourcePath, outputPath, platform, size);
+    renditionCache.set(cacheKey, contents);
+    return contents;
+  });
+
+  const ios = yield* render("iOS", 1024);
+  const icoRenditions = yield* Effect.forEach(
+    WINDOWS_ICON_SIZES,
+    (size) => render("iOS", size).pipe(Effect.map((contents) => ({ size, contents }))),
+    { concurrency: 1 },
+  );
+  const ico = yield* Effect.try({
+    try: () => encodePngIco(icoRenditions),
+    catch: (cause) => new IconExportEncodingError({ variant: variant.label, cause }),
+  });
+
+  return new Map<string, Buffer>([
+    [variant.outputs.ios, ios],
+    [variant.outputs.universal, ios],
+    [variant.outputs.appleTouch, yield* render("iOS", 180)],
+    [variant.outputs.favicon16, yield* render("iOS", 16)],
+    [variant.outputs.favicon32, yield* render("iOS", 32)],
+    [variant.outputs.faviconIco, ico],
+    [variant.outputs.windowsIco, ico],
+  ]);
+});
+
+const logManualMacOsExportInstructions = Effect.fn("iconExport.logManualMacOsExportInstructions")(
+  function* () {
+    yield* Console.warn(
+      [
+        "macOS icons require Icon Composer's GUI-only pre-Tahoe preset and were not changed.",
+        "Export each source with Platform: macOS pre-Tahoe, Appearance: Default, Size: 1024pt, Scale: 1×:",
+        ...ICON_VARIANTS.map((variant) => `- ${variant.source} -> ${variant.outputs.macos}`),
+        "See assets/README.md for the complete workflow.",
+        "",
+        "Copy/paste this prompt into Codex to perform the native exports:",
+        "---",
+        ...MACOS_EXPORT_CODEX_PROMPT,
+        "---",
+      ].join("\n"),
+    );
+  },
+);
+
+const writeAtomically = Effect.fn("iconExport.writeAtomically")(function* (
+  repositoryRoot: string,
+  relativePath: string,
+  contents: Buffer,
+) {
+  const fs = yield* FileSystem.FileSystem;
+  const path = yield* Path.Path;
+  const targetPath = path.join(repositoryRoot, relativePath);
+  const targetDirectory = path.dirname(targetPath);
+  yield* fs.makeDirectory(targetDirectory, { recursive: true }).pipe(
+    Effect.mapError(
+      (cause) =>
+        new IconExportFileSystemError({
+          operation: "make-directory",
+          path: targetDirectory,
+          cause,
+        }),
+    ),
+  );
+  const temporaryPath = yield* fs
+    .makeTempFileScoped({
+      directory: targetDirectory,
+      prefix: ".t3-icon-export-",
+      suffix: ".tmp",
+    })
+    .pipe(
+      Effect.mapError(
+        (cause) =>
+          new IconExportFileSystemError({
+            operation: "make-temp-file",
+            path: targetDirectory,
+            cause,
+          }),
+      ),
+    );
+  yield* fs.writeFile(temporaryPath, contents).pipe(
+    Effect.mapError(
+      (cause) =>
+        new IconExportFileSystemError({
+          operation: "write-file",
+          path: temporaryPath,
+          cause,
+        }),
+    ),
+  );
+  yield* fs.rename(temporaryPath, targetPath).pipe(
+    Effect.mapError(
+      (cause) =>
+        new IconExportFileSystemError({
+          operation: "rename-file",
+          path: targetPath,
+          cause,
+        }),
+    ),
+  );
+});
+
+const isCurrent = Effect.fn("iconExport.isCurrent")(function* (
+  repositoryRoot: string,
+  relativePath: string,
+  expected: Buffer,
+) {
+  const fs = yield* FileSystem.FileSystem;
+  const path = yield* Path.Path;
+  const targetPath = path.join(repositoryRoot, relativePath);
+  const exists = yield* fs.exists(targetPath).pipe(
+    Effect.mapError(
+      (cause) =>
+        new IconExportFileSystemError({
+          operation: "check-path",
+          path: targetPath,
+          cause,
+        }),
+    ),
+  );
+  if (!exists) return false;
+
+  const actual = yield* fs.readFile(targetPath).pipe(
+    Effect.mapError(
+      (cause) =>
+        new IconExportFileSystemError({
+          operation: "read-file",
+          path: targetPath,
+          cause,
+        }),
+    ),
+  );
+  return Buffer.from(actual).equals(expected);
+});
+
+export const exportBrandIcons = Effect.fn("exportBrandIcons")(function* (checkOnly: boolean) {
+  const fs = yield* FileSystem.FileSystem;
+  const repositoryRoot = yield* RepositoryRoot;
+  const tool = yield* resolveIconComposerTool();
+  const temporaryDirectory = yield* fs
+    .makeTempDirectoryScoped({
+      prefix: "t3-icon-export-",
+    })
+    .pipe(
+      Effect.mapError(
+        (cause) =>
+          new IconExportFileSystemError({
+            operation: "make-temp-directory",
+            path: "system temporary directory",
+            cause,
+          }),
+      ),
+    );
+  yield* Console.log(
+    `Exporting icons with Icon Composer ${tool.version}, design generation ${DESIGN_GENERATION}.`,
+  );
+
+  const generated = new Map<string, Buffer>();
+  for (const variant of ICON_VARIANTS) {
+    yield* Console.log(`Rendering ${variant.label} from ${variant.source}...`);
+    const variantAssets = yield* renderVariant(
+      tool.path,
+      repositoryRoot,
+      temporaryDirectory,
+      variant,
+    );
+    for (const [relativePath, contents] of variantAssets) {
+      generated.set(relativePath, contents);
+    }
+  }
+
+  if (checkOnly) {
+    const stale = yield* Effect.filter(
+      [...generated.entries()],
+      ([relativePath, contents]) =>
+        isCurrent(repositoryRoot, relativePath, contents).pipe(Effect.map((current) => !current)),
+      { concurrency: "unbounded" },
+    );
+    if (stale.length > 0) {
+      return yield* new IconExportAssetsStaleError({
+        paths: stale.map(([relativePath]) => relativePath),
+      });
+    }
+    yield* Console.log(`All ${generated.size} generated icon assets are current.`);
+    yield* logManualMacOsExportInstructions();
+    return;
+  }
+
+  yield* Effect.forEach(
+    generated,
+    ([relativePath, contents]) => writeAtomically(repositoryRoot, relativePath, contents),
+    { concurrency: 1, discard: true },
+  );
+  yield* Console.log(`Updated ${generated.size} generated icon assets.`);
+  yield* logManualMacOsExportInstructions();
+});
+
+export const exportBrandIconsCommand = Command.make(
+  "export-brand-icons",
+  {
+    check: Flag.boolean("check").pipe(
+      Flag.withDescription("Verify generated icon assets without modifying files."),
+      Flag.withDefault(false),
+    ),
+  },
+  ({ check }) => exportBrandIcons(check).pipe(Effect.scoped),
+).pipe(
+  Command.withDescription(
+    "Export development, preview, and production assets from Icon Composer projects.",
+  ),
+);
+
+if (import.meta.main) {
+  Command.run(exportBrandIconsCommand, { version: "0.0.0" }).pipe(
+    Effect.provide(NodeServices.layer),
+    NodeRuntime.runMain,
+  );
+}
diff --git a/scripts/lib/brand-assets.test.ts b/scripts/lib/brand-assets.test.ts
index 8e1875e8d274..6ab3c6a3a293 100644
--- a/scripts/lib/brand-assets.test.ts
+++ b/scripts/lib/brand-assets.test.ts
@@ -55,4 +55,19 @@ describe("brand-assets", () => {
     expect(resolveWebAssetBrandForChannel("latest")).toBe("production");
     expect(resolveWebAssetBrandForChannel("nightly")).toBe("nightly");
   });
+
+  it("keeps development, nightly, and production icon families separate", () => {
+    expect([
+      BRAND_ASSET_PATHS.developmentIconComposerProject,
+      BRAND_ASSET_PATHS.nightlyIconComposerProject,
+      BRAND_ASSET_PATHS.productionIconComposerProject,
+    ]).toEqual([
+      "assets/dev/app-icon.icon",
+      "assets/nightly/app-icon.icon",
+      "assets/prod/app-icon.icon",
+    ]);
+    expect(BRAND_ASSET_PATHS.developmentDesktopIconPng).toMatch(/^assets\/dev\/blueprint-/);
+    expect(BRAND_ASSET_PATHS.nightlyMacIconPng).toMatch(/^assets\/nightly\/nightly-/);
+    expect(BRAND_ASSET_PATHS.productionMacIconPng).toMatch(/^assets\/prod\/black-/);
+  });
 });
diff --git a/scripts/lib/brand-assets.ts b/scripts/lib/brand-assets.ts
index c326c43ff575..c4de2eb820b5 100644
--- a/scripts/lib/brand-assets.ts
+++ b/scripts/lib/brand-assets.ts
@@ -1,5 +1,13 @@
 export const BRAND_ASSET_PATHS = {
+  developmentIconComposerProject: "assets/dev/app-icon.icon",
+  developmentIosIconPng: "assets/dev/blueprint-ios-1024.png",
+  developmentUniversalIconPng: "assets/dev/blueprint-universal-1024.png",
+
+  // Fork-only: opt-in macOS 26 appearance-aware icon, populated manually via
+  // Apple Icon Composer. See docs/custom-alpha-workflow.md#macos-26-icon-method.
   productionMacIconComposer: "assets/prod/icon.icon",
+  productionIconComposerProject: "assets/prod/app-icon.icon",
+  productionIosIconPng: "assets/prod/black-ios-1024.png",
   productionMacIconPng: "assets/prod/black-macos-1024.png",
   productionLinuxIconPng: "assets/prod/black-universal-1024.png",
   productionWindowsIconIco: "assets/prod/t3-black-windows.ico",
@@ -8,13 +16,15 @@ export const BRAND_ASSET_PATHS = {
   productionWebFavicon32Png: "assets/prod/t3-black-web-favicon-32x32.png",
   productionWebAppleTouchIconPng: "assets/prod/t3-black-web-apple-touch-180.png",
 
-  nightlyMacIconPng: "assets/nightly/blueprint-macos-1024.png",
-  nightlyLinuxIconPng: "assets/nightly/blueprint-universal-1024.png",
-  nightlyWindowsIconIco: "assets/nightly/blueprint-windows.ico",
-  nightlyWebFaviconIco: "assets/nightly/blueprint-web-favicon.ico",
-  nightlyWebFavicon16Png: "assets/nightly/blueprint-web-favicon-16x16.png",
-  nightlyWebFavicon32Png: "assets/nightly/blueprint-web-favicon-32x32.png",
-  nightlyWebAppleTouchIconPng: "assets/nightly/blueprint-web-apple-touch-180.png",
+  nightlyIconComposerProject: "assets/nightly/app-icon.icon",
+  nightlyIosIconPng: "assets/nightly/nightly-ios-1024.png",
+  nightlyMacIconPng: "assets/nightly/nightly-macos-1024.png",
+  nightlyLinuxIconPng: "assets/nightly/nightly-universal-1024.png",
+  nightlyWindowsIconIco: "assets/nightly/nightly-windows.ico",
+  nightlyWebFaviconIco: "assets/nightly/nightly-web-favicon.ico",
+  nightlyWebFavicon16Png: "assets/nightly/nightly-web-favicon-16x16.png",
+  nightlyWebFavicon32Png: "assets/nightly/nightly-web-favicon-32x32.png",
+  nightlyWebAppleTouchIconPng: "assets/nightly/nightly-web-apple-touch-180.png",
 
   developmentDesktopIconPng: "assets/dev/blueprint-macos-1024.png",
   developmentWindowsIconIco: "assets/dev/blueprint-windows.ico",
diff --git a/scripts/lib/icon-export.test.ts b/scripts/lib/icon-export.test.ts
new file mode 100644
index 000000000000..3db6f22cbdbc
--- /dev/null
+++ b/scripts/lib/icon-export.test.ts
@@ -0,0 +1,47 @@
+import { assert, describe, it } from "@effect/vitest";
+
+import { encodePngIco, readPngDimensions } from "./icon-export.ts";
+
+const pngHeader = (width: number, height: number) => {
+  const contents = Buffer.alloc(24);
+  Buffer.from([0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a]).copy(contents);
+  contents.write("IHDR", 12, "ascii");
+  contents.writeUInt32BE(width, 16);
+  contents.writeUInt32BE(height, 20);
+  return contents;
+};
+
+describe("icon export", () => {
+  it("reads dimensions from a PNG IHDR chunk", () => {
+    assert.deepEqual(readPngDimensions(pngHeader(1024, 512)), { width: 1024, height: 512 });
+  });
+
+  it("encodes PNG renditions into an ICO directory", () => {
+    const small = pngHeader(16, 16);
+    const large = pngHeader(256, 256);
+    const ico = encodePngIco([
+      { size: 16, contents: small },
+      { size: 256, contents: large },
+    ]);
+
+    assert.equal(ico.readUInt16LE(2), 1);
+    assert.equal(ico.readUInt16LE(4), 2);
+    assert.equal(ico.readUInt8(6), 16);
+    assert.equal(ico.readUInt8(22), 0);
+    assert.equal(ico.readUInt32LE(18), 38);
+    assert.equal(ico.readUInt32LE(34), 38 + small.length);
+    assert.deepEqual(ico.subarray(38, 38 + small.length), small);
+    assert.deepEqual(ico.subarray(38 + small.length), large);
+  });
+
+  it("rejects duplicate ICO rendition sizes", () => {
+    assert.throws(
+      () =>
+        encodePngIco([
+          { size: 32, contents: pngHeader(32, 32) },
+          { size: 32, contents: pngHeader(32, 32) },
+        ]),
+      /provided more than once/,
+    );
+  });
+});
diff --git a/scripts/lib/icon-export.ts b/scripts/lib/icon-export.ts
new file mode 100644
index 000000000000..f48228a94fd3
--- /dev/null
+++ b/scripts/lib/icon-export.ts
@@ -0,0 +1,72 @@
+const PNG_SIGNATURE = Buffer.from([0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a]);
+
+export const WINDOWS_ICON_SIZES = [16, 24, 32, 48, 64, 128, 256] as const;
+
+export interface PngIconImage {
+  readonly size: number;
+  readonly contents: Buffer;
+}
+
+export function readPngDimensions(contents: Buffer): {
+  readonly width: number;
+  readonly height: number;
+} {
+  if (
+    contents.length < 24 ||
+    !contents.subarray(0, PNG_SIGNATURE.length).equals(PNG_SIGNATURE) ||
+    contents.toString("ascii", 12, 16) !== "IHDR"
+  ) {
+    throw new Error("Icon Composer produced an invalid PNG.");
+  }
+
+  return {
+    width: contents.readUInt32BE(16),
+    height: contents.readUInt32BE(20),
+  };
+}
+
+/** Encodes PNG renditions directly into a modern, multi-resolution ICO file. */
+export function encodePngIco(images: ReadonlyArray<PngIconImage>): Buffer {
+  if (images.length === 0) {
+    throw new Error("An ICO file requires at least one PNG rendition.");
+  }
+
+  const seenSizes = new Set<number>();
+  for (const image of images) {
+    if (!Number.isInteger(image.size) || image.size < 1 || image.size > 256) {
+      throw new Error(`ICO rendition size must be an integer from 1 to 256, got ${image.size}.`);
+    }
+    if (seenSizes.has(image.size)) {
+      throw new Error(`ICO rendition size ${image.size} was provided more than once.`);
+    }
+    if (image.contents.length === 0) {
+      throw new Error(`ICO rendition ${image.size}x${image.size} is empty.`);
+    }
+    seenSizes.add(image.size);
+  }
+
+  const headerSize = 6;
+  const directoryEntrySize = 16;
+  const directorySize = directoryEntrySize * images.length;
+  const header = Buffer.alloc(headerSize + directorySize);
+  header.writeUInt16LE(0, 0);
+  header.writeUInt16LE(1, 2);
+  header.writeUInt16LE(images.length, 4);
+
+  let imageOffset = header.length;
+  images.forEach((image, index) => {
+    const entryOffset = headerSize + index * directoryEntrySize;
+    const encodedSize = image.size === 256 ? 0 : image.size;
+    header.writeUInt8(encodedSize, entryOffset);
+    header.writeUInt8(encodedSize, entryOffset + 1);
+    header.writeUInt8(0, entryOffset + 2);
+    header.writeUInt8(0, entryOffset + 3);
+    header.writeUInt16LE(1, entryOffset + 4);
+    header.writeUInt16LE(32, entryOffset + 6);
+    header.writeUInt32LE(image.contents.length, entryOffset + 8);
+    header.writeUInt32LE(imageOffset, entryOffset + 12);
+    imageOffset += image.contents.length;
+  });
+
+  return Buffer.concat([header, ...images.map((image) => image.contents)]);
+}