diff --git a/apps/discord-bot/src/features/ResponseBridge.ts b/apps/discord-bot/src/features/ResponseBridge.ts
index 82a421a4dbf8..f7716ca3dc3f 100644
--- a/apps/discord-bot/src/features/ResponseBridge.ts
+++ b/apps/discord-bot/src/features/ResponseBridge.ts
@@ -1,5 +1,6 @@
 // @effect-diagnostics anyUnknownInErrorContext:off missingEffectContext:off globalFetchInEffect:off unknownInEffectCatch:off nodeBuiltinImport:off
 import * as NodeFSP from "node:fs/promises";
+import * as NodePath from "node:path";
 import type {
   ChatImageAttachment,
   OrchestrationThread,
@@ -48,6 +49,7 @@ import {
   guessFileMimeType,
   isLocalFileSrc,
   replaceMarkdownLocalFileLinks,
+  resolveLocalFilePathOnDisk,
   stripMarkdownLocalFileLinks,
   type MarkdownLocalFileRef,
 } from "../presentation/markdownFiles.ts";
@@ -2878,6 +2880,7 @@ export const runBridge = (
       refs: ReadonlyArray<MarkdownLocalFileRef>,
       alreadyPosted: ReadonlyArray<string>,
       maxFiles: number,
+      worktreePath: string | null,
     ) =>
       Effect.gen(function* () {
         const posted = new Set(alreadyPosted);
@@ -2891,13 +2894,20 @@ export const runBridge = (
         const files: DiscordUploadFile[] = [];
         const loadedSrcs: string[] = [];
         for (const ref of pending) {
-          const filePath = assertFilesystemFilePath(ref.src);
+          // Agents write worktree-relative paths (e.g. `.plans/note.md`). Resolve
+          // against the thread worktree before reading — bot cwd is not the project.
+          const resolved =
+            resolveLocalFilePathOnDisk(ref.src, worktreePath) ??
+            resolveLocalFilePathOnDisk(ref.rawSrc, worktreePath) ??
+            assertFilesystemFilePath(ref.src);
+          const filePath = resolved;
           const name = fileNameForLocalFileRef(ref);
           const mime = guessFileMimeType(filePath);
 
           yield* Effect.logInfo("Loading markdown file for Discord multipart", {
             rawSrc: ref.rawSrc,
             filePath,
+            worktreePath,
             name,
           });
 
@@ -2920,11 +2930,23 @@ export const runBridge = (
             continue;
           }
 
+          // Asset URL preview rejects most text types (.md). Prefer a worktree-relative
+          // path for the RPC so the server can resolve under the project root.
+          const assetPathForUrl = (() => {
+            const raw = assertFilesystemFilePath(ref.src);
+            if (!NodePath.isAbsolute(raw)) return raw.replace(/^\.\//u, "");
+            const root = worktreePath?.trim() ?? "";
+            if (root !== "" && raw.startsWith(root)) {
+              const rel = raw.slice(root.length).replace(/^[/\\]+/u, "");
+              if (rel !== "") return rel;
+            }
+            return raw;
+          })();
+
           const fromAsset = yield* Effect.gen(function* () {
-            const assetPath = assertFilesystemFilePath(ref.src);
             const url = yield* t3.createWorkspaceFileUrl({
               threadId: input.t3ThreadId as ThreadId,
-              path: assetPath,
+              path: assetPathForUrl,
             });
             const response = yield* Effect.tryPromise({
               try: () => globalThis.fetch(url),
@@ -2932,7 +2954,7 @@ export const runBridge = (
             });
             if (!response.ok) {
               yield* Effect.logWarning(
-                `Asset file download failed (${response.status}) for ${assetPath}`,
+                `Asset file download failed (${response.status}) for ${assetPathForUrl}`,
               );
               return null as DiscordUploadFile | null;
             }
@@ -2949,7 +2971,7 @@ export const runBridge = (
             Effect.catchCause((cause) =>
               Effect.gen(function* () {
                 yield* Effect.logWarning(
-                  `Could not load markdown file for Discord (disk+asset): raw=${ref.rawSrc} path=${filePath}`,
+                  `Could not load markdown file for Discord (disk+asset): raw=${ref.rawSrc} path=${filePath} worktree=${worktreePath ?? "null"}`,
                 );
                 yield* Effect.logError(cause);
                 return null as DiscordUploadFile | null;
@@ -3593,6 +3615,7 @@ export const runBridge = (
             pendingMarkdownFiles,
             state.postedMarkdownFileSrcs,
             fileSlotsLeft,
+            worktreePath,
           );
           const files = [...imageFiles, ...mdLoaded.files, ...linkedFilesLoaded.files];
           if (files.length === 0) return;
@@ -3675,6 +3698,7 @@ export const runBridge = (
           pendingMarkdownFiles,
           state.postedMarkdownFileSrcs,
           slots,
+          worktreePath,
         );
         files.push(...linkedFilesLoaded.files);
 
diff --git a/apps/discord-bot/src/presentation/markdownFiles.test.ts b/apps/discord-bot/src/presentation/markdownFiles.test.ts
index 6594bf263d25..7b6700cd2a5a 100644
--- a/apps/discord-bot/src/presentation/markdownFiles.test.ts
+++ b/apps/discord-bot/src/presentation/markdownFiles.test.ts
@@ -1,3 +1,7 @@
+// @effect-diagnostics nodeBuiltinImport:off
+import * as NodeFS from "node:fs";
+import * as NodeOS from "node:os";
+import * as NodePath from "node:path";
 import { describe, expect, it } from "vite-plus/test";
 
 import {
@@ -6,6 +10,7 @@ import {
   guessFileMimeType,
   isLocalFileSrc,
   replaceMarkdownLocalFileLinks,
+  resolveLocalFilePathOnDisk,
   stripMarkdownLocalFileLinks,
 } from "./markdownFiles.ts";
 
@@ -85,3 +90,29 @@ describe("local file helpers", () => {
     expect(guessFileMimeType("/tmp/voice.mp3")).toBe("audio/mpeg");
   });
 });
+
+describe("resolveLocalFilePathOnDisk", () => {
+  it("resolves worktree-relative plan paths that agents emit", () => {
+    const tempRoot = NodeFS.mkdtempSync(NodePath.join(NodeOS.tmpdir(), "t3-discord-md-file-"));
+    try {
+      const plansDir = NodePath.join(tempRoot, ".plans");
+      const relativeFile = ".plans/abas-markisen-agent-collisions.md";
+      const absoluteFile = NodePath.join(tempRoot, relativeFile);
+      NodeFS.mkdirSync(plansDir, { recursive: true });
+      NodeFS.writeFileSync(absoluteFile, "# note\n", "utf8");
+
+      expect(resolveLocalFilePathOnDisk(relativeFile, tempRoot)).toBe(
+        NodePath.normalize(absoluteFile),
+      );
+      expect(resolveLocalFilePathOnDisk(`./${relativeFile}`, tempRoot)).toBe(
+        NodePath.normalize(absoluteFile),
+      );
+      // Absolute path still works when present.
+      expect(resolveLocalFilePathOnDisk(absoluteFile, null)).toBe(NodePath.normalize(absoluteFile));
+      // Without worktree, bot cwd cannot see the project-relative path.
+      expect(resolveLocalFilePathOnDisk(relativeFile, null)).toBeNull();
+    } finally {
+      NodeFS.rmSync(tempRoot, { recursive: true, force: true });
+    }
+  });
+});
diff --git a/apps/discord-bot/src/presentation/markdownFiles.ts b/apps/discord-bot/src/presentation/markdownFiles.ts
index 99cce986295c..430b31f8410c 100644
--- a/apps/discord-bot/src/presentation/markdownFiles.ts
+++ b/apps/discord-bot/src/presentation/markdownFiles.ts
@@ -1,3 +1,7 @@
+// @effect-diagnostics nodeBuiltinImport:off
+import * as NodeFS from "node:fs";
+import * as NodePath from "node:path";
+
 import {
   assertFilesystemPath,
   guessImageMimeType,
@@ -145,6 +149,45 @@ export function fileNameForLocalFileRef(ref: MarkdownLocalFileRef): string {
   return base;
 }
 
+/**
+ * Resolve a local markdown-linked file to an absolute path on disk.
+ *
+ * Agents usually write worktree-relative targets (`.plans/note.md`, `./out.csv`).
+ * The Discord bot process cwd is the bot package — resolve against `worktreePath`
+ * first so relative embeds actually upload.
+ */
+export function resolveLocalFilePathOnDisk(
+  path: string,
+  worktreePath?: string | null,
+): string | null {
+  const normalized = assertFilesystemPath(path);
+  if (normalized === "" || /^https?:\/\//i.test(normalized) || /^data:/i.test(normalized)) {
+    return null;
+  }
+
+  if (NodePath.isAbsolute(normalized)) {
+    return NodeFS.existsSync(normalized) ? NodePath.normalize(normalized) : null;
+  }
+
+  const rel = normalized.replace(/^\.\//u, "");
+  const roots: string[] = [];
+  const worktree = worktreePath?.trim() ?? "";
+  if (worktree !== "") {
+    roots.push(worktree);
+  }
+  // Fallbacks when worktree is unknown (local / no-worktree threads).
+  roots.push(process.cwd());
+
+  for (const root of roots) {
+    const candidate = NodePath.join(root, rel);
+    if (NodeFS.existsSync(candidate) && NodeFS.statSync(candidate).isFile()) {
+      return NodePath.normalize(candidate);
+    }
+  }
+
+  return null;
+}
+
 export function guessFileMimeType(filePath: string): string {
   const lower = filePath.toLowerCase();
   if (/\.(png|jpe?g|gif|webp|bmp|svg)$/i.test(lower)) {