feat(web): attach a provider account to each project

apps/server/src/orchestration/decider.ts

@@ -288,9 +288,7 @@ export const decideOrchestrationCommand = Effect.fn("decideOrchestrationCommand"
           ...(command.defaultModelSelection !== undefined
             ? { defaultModelSelection: command.defaultModelSelection }
             : {}),
-          ...(command.gitHubAccount !== undefined
-            ? { gitHubAccount: command.gitHubAccount }
-            : {}),
+          ...(command.gitHubAccount !== undefined ? { gitHubAccount: command.gitHubAccount } : {}),
           ...(command.scripts !== undefined ? { scripts: command.scripts } : {}),
           updatedAt: occurredAt,
         },

apps/server/src/sourceControl/GitHubAccountResolver.test.ts

@@ -119,7 +119,9 @@ describe("GitHubAccountResolver.resolveForCwd", () => {
       Effect.provide(
         layerFor(
           shellSnapshot({
-            projects: [projectShell({ id: "app", workspaceRoot: "/repos/app", gitHubAccount: null })],
+            projects: [
+              projectShell({ id: "app", workspaceRoot: "/repos/app", gitHubAccount: null }),
+            ],
             threads: [],
           }),
         ),
@@ -137,14 +139,7 @@ describe("GitHubAccountResolver.resolveForCwd", () => {
         token: "gho_secret",
       });
       const call = mockRun.mock.calls[0]?.[0];
-      assert.deepEqual(call?.args, [
-        "auth",
-        "token",
-        "--user",
-        "octo",
-        "--hostname",
-        "github.com",
-      ]);
+      assert.deepEqual(call?.args, ["auth", "token", "--user", "octo", "--hostname", "github.com"]);
     }).pipe(
       Effect.provide(
         layerFor(

apps/server/src/sourceControl/GitHubAccountResolver.ts

@@ -130,10 +130,7 @@ export const make = Effect.gen(function* () {
       Effect.catch(() => Effect.succeed(null)),
     );
 
-  const resolveToken = (
-    cwd: string,
-    account: GitHubAccountRef,
-  ): Effect.Effect<string | null> =>
+  const resolveToken = (cwd: string, account: GitHubAccountRef): Effect.Effect<string | null> =>
     Effect.gen(function* () {
       const now = yield* Clock.currentTimeMillis;
       const cache = yield* Ref.get(tokenCache);

apps/web/src/components/ProjectDefaultAgentField.tsx

@@ -0,0 +1,199 @@
+import { useMemo } from "react";
+
+import { useAtomValue } from "@effect/atom-react";
+import { scopeProjectRef } from "@t3tools/client-runtime/environment";
+import type {
+  EnvironmentId,
+  ModelSelection,
+  ProjectId,
+  ProviderInstanceId,
+} from "@t3tools/contracts";
+
+import {
+  applyProviderInstanceSettings,
+  deriveProviderInstanceEntries,
+  getDefaultProviderInstanceModel,
+  isProviderInstancePickerVisible,
+  sortProviderInstanceEntries,
+  type ProviderInstanceEntry,
+} from "../providerInstances";
+import { useProject } from "../state/entities";
+import { environmentServerConfigsAtom } from "../state/server";
+import { ProviderInstanceIcon } from "./chat/ProviderInstanceIcon";
+import {
+  Select,
+  SelectItem,
+  SelectPopup,
+  SelectTrigger,
+  SelectValue,
+} from "./ui/select";
+
+// Sentinel routing value for "no pinned account": the composer falls back to
+// the first available provider instance for the environment. Kept out of the
+// `ProviderInstanceId` space so it can never collide with a real instance id.
+const USE_DEFAULT_VALUE = "__t3_project_default__";
+
+/**
+ * Per-project "default agent" control. Picks which configured provider
+ * instance (i.e. which account/subscription — e.g. two separate Claude
+ * logins) new threads in a project start on, plus that instance's model.
+ *
+ * The selection is written to the project's `defaultModelSelection`; the chat
+ * composer already resolves a new thread's provider from the project default
+ * when the draft doesn't override it, so pinning an account here routes every
+ * fresh thread in the project to that account's credentials.
+ *
+ * Provider instances are read per-environment: a project's account choices are
+ * exactly the accounts configured on the server that hosts it.
+ */
+export function ProjectDefaultAgentField(props: {
+  environmentId: EnvironmentId;
+  projectId: ProjectId;
+  onChange: (selection: ModelSelection | null) => void;
+  disabled?: boolean;
+  idPrefix: string;
+}) {
+  const { environmentId, projectId, onChange, disabled, idPrefix } = props;
+  const projectRef = useMemo(
+    () => scopeProjectRef(environmentId, projectId),
+    [environmentId, projectId],
+  );
+  // Read the selection live so the control reflects the persisted value even
+  // when the enclosing dialog renders from a captured project snapshot.
+  const value = useProject(projectRef)?.defaultModelSelection ?? null;
+  const serverConfigs = useAtomValue(environmentServerConfigsAtom);
+  const config = serverConfigs.get(environmentId) ?? null;
+
+  const entries = useMemo(() => {
+    const providers = config?.providers ?? [];
+    const settings = config?.settings;
+    const derived = deriveProviderInstanceEntries(providers);
+    const withSettings = settings
+      ? applyProviderInstanceSettings(derived, settings)
+      : derived;
+    return sortProviderInstanceEntries(withSettings).filter(isProviderInstancePickerVisible);
+  }, [config?.providers, config?.settings]);
+
+  const providers = config?.providers ?? [];
+
+  const selectedInstanceId = value?.instanceId ?? null;
+  const selectedEntry: ProviderInstanceEntry | undefined = selectedInstanceId
+    ? entries.find((entry) => entry.instanceId === selectedInstanceId)
+    : undefined;
+
+  // A pinned instance that has since been removed/disabled still shows so the
+  // user can see (and clear) the stale pin instead of it silently vanishing.
+  const showStalePin = selectedInstanceId !== null && selectedEntry === undefined;
+
+  const handleAccountChange = (next: string | null) => {
+    if (next === null || next === USE_DEFAULT_VALUE) {
+      onChange(null);
+      return;
+    }
+    const instanceId = next as ProviderInstanceId;
+    // Keep the model when re-selecting the same instance; otherwise reset to
+    // that instance's default so we never persist a cross-account model pair.
+    const model =
+      value?.instanceId === instanceId
+        ? value.model
+        : getDefaultProviderInstanceModel(providers, instanceId);
+    if (!model) {
+      // Instance reports no models yet (probe pending); pinning it now would
+      // produce an invalid selection, so leave the project on its default.
+      onChange(null);
+      return;
+    }
+    onChange({ instanceId, model });
+  };
+
+  const handleModelChange = (slug: string | null) => {
+    if (!selectedInstanceId || slug === null) return;
+    onChange({ instanceId: selectedInstanceId, model: slug });
+  };
+
+  const models = selectedEntry?.models ?? [];
+  const accountSelectValue = selectedInstanceId ?? USE_DEFAULT_VALUE;
+
+  return (
+    <div className="grid gap-4 sm:grid-cols-2 sm:gap-3">
+      <label className="grid min-w-0 gap-1.5" htmlFor={`${idPrefix}-account`}>
+        <span className="font-medium text-foreground">Default agent</span>
+        <Select value={accountSelectValue} onValueChange={handleAccountChange} disabled={disabled}>
+          <SelectTrigger id={`${idPrefix}-account`} className="w-full sm:min-h-7.5">
+            <SelectValue>
+              {selectedEntry ? (
+                <span className="flex min-w-0 items-center gap-2">
+                  <ProviderInstanceIcon
+                    driverKind={selectedEntry.driverKind}
+                    displayName={selectedEntry.displayName}
+                    accentColor={selectedEntry.accentColor}
+                    className="size-4"
+                    iconClassName="size-4"
+                  />
+                  <span className="min-w-0 truncate">{selectedEntry.displayName}</span>
+                </span>
+              ) : showStalePin ? (
+                <span className="min-w-0 truncate text-muted-foreground">
+                  {selectedInstanceId} (unavailable)
+                </span>
+              ) : (
+                "Use default account"
+              )}
+            </SelectValue>
+          </SelectTrigger>
+          <SelectPopup align="start" alignItemWithTrigger={false}>
+            <SelectItem hideIndicator value={USE_DEFAULT_VALUE}>
+              Use default account
+            </SelectItem>
+            {entries.map((entry) => (
+              <SelectItem hideIndicator key={entry.instanceId} value={entry.instanceId}>
+                <span className="flex min-w-0 items-center gap-2">
+                  <ProviderInstanceIcon
+                    driverKind={entry.driverKind}
+                    displayName={entry.displayName}
+                    accentColor={entry.accentColor}
+                    className="size-4"
+                    iconClassName="size-4"
+                  />
+                  <span className="min-w-0 truncate">{entry.displayName}</span>
+                </span>
+              </SelectItem>
+            ))}
+            {showStalePin ? (
+              <SelectItem hideIndicator value={selectedInstanceId}>
+                <span className="min-w-0 truncate text-muted-foreground">
+                  {selectedInstanceId} (unavailable)
+                </span>
+              </SelectItem>
+            ) : null}
+          </SelectPopup>
+        </Select>
+      </label>
+      <label className="grid min-w-0 gap-1.5" htmlFor={`${idPrefix}-model`}>
+        <span className="font-medium text-foreground">Model</span>
+        <Select
+          value={value?.model ?? ""}
+          onValueChange={handleModelChange}
+          disabled={disabled || !selectedEntry || models.length === 0}
+        >
+          <SelectTrigger id={`${idPrefix}-model`} className="w-full sm:min-h-7.5">
+            <SelectValue>
+              {selectedEntry
+                ? (models.find((model) => model.slug === value?.model)?.name ??
+                  value?.model ??
+                  "Default model")
+                : "—"}
+            </SelectValue>
+          </SelectTrigger>
+          <SelectPopup align="start" alignItemWithTrigger={false}>
+            {models.map((model) => (
+              <SelectItem hideIndicator key={model.slug} value={model.slug}>
+                {model.name}
+              </SelectItem>
+            ))}
+          </SelectPopup>
+        </Select>
+      </label>
+    </div>
+  );
+}

apps/web/src/components/Sidebar.tsx

@@ -21,6 +21,7 @@ import {
   ThreadStatusLabel,
   ThreadWorktreeIndicator,
 } from "./ThreadStatusIndicators";
+import { ProjectDefaultAgentField } from "./ProjectDefaultAgentField";
 import { ProjectFavicon } from "./ProjectFavicon";
 import { useAtomValue } from "@effect/atom-react";
 import { autoAnimate } from "@formkit/auto-animate";
@@ -43,6 +44,7 @@ import { restrictToFirstScrollableAncestor, restrictToVerticalAxis } from "@dnd-
 import { CSS } from "@dnd-kit/utilities";
 import {
   type ContextMenuItem,
+  type ModelSelection,
   ProjectId,
   type ScopedThreadRef,
   type ResolvedKeybindingsConfig,
@@ -2068,6 +2070,26 @@ const SidebarProjectItem = memo(function SidebarProjectItem(props: SidebarProjec
     }
   }, [closeProjectRenameDialog, projectRenameTarget, projectRenameTitle, updateProject]);
 
+  const updateProjectDefaultModelSelection = useCallback(
+    async (member: SidebarProjectGroupMember, selection: ModelSelection | null) => {
+      const result = await updateProject({
+        environmentId: member.environmentId,
+        input: { projectId: member.id, defaultModelSelection: selection },
+      });
+      if (result._tag === "Failure" && !isAtomCommandInterrupted(result)) {
+        const error = squashAtomCommandFailure(result);
+        toastManager.add(
+          stackedThreadToast({
+            type: "error",
+            title: "Failed to update project agent",
+            description: error instanceof Error ? error.message : "An error occurred.",
+          }),
+        );
+      }
+    },
+    [updateProject],
+  );
+
   const closeProjectGroupingDialog = useCallback(() => {
     setProjectGroupingTarget(null);
     setProjectGroupingSelection("inherit");
@@ -2394,6 +2416,16 @@ const SidebarProjectItem = memo(function SidebarProjectItem(props: SidebarProjec
                 Environment: {projectRenameTarget.environmentLabel}
               </p>
             ) : null}
+            {projectRenameTarget ? (
+              <ProjectDefaultAgentField
+                idPrefix={`project-agent-${projectRenameTarget.physicalProjectKey}`}
+                environmentId={projectRenameTarget.environmentId}
+                projectId={projectRenameTarget.id}
+                onChange={(selection) => {
+                  void updateProjectDefaultModelSelection(projectRenameTarget, selection);
+                }}
+              />
+            ) : null}
           </DialogPanel>
           <DialogFooter>
             <Button variant="outline" onClick={closeProjectRenameDialog}>

apps/web/src/components/SidebarV2.tsx

@@ -14,6 +14,7 @@ import {
 } from "@t3tools/client-runtime/environment";
 import type {
   GitHubAccountRef,
+  ModelSelection,
   ScopedThreadRef,
   SidebarProjectGroupingMode,
 } from "@t3tools/contracts";
@@ -137,6 +138,7 @@ import {
   type SnoozePreset,
 } from "./Sidebar.snooze";
 import { GitHubIcon } from "./Icons";
+import { ProjectDefaultAgentField } from "./ProjectDefaultAgentField";
 import { ProjectFavicon } from "./ProjectFavicon";
 import { ProviderInstanceIcon } from "./chat/ProviderInstanceIcon";
 import { getTriggerDisplayModelLabel } from "./chat/providerIconUtils";
@@ -1022,10 +1024,7 @@ function githubAccountValue(account: { readonly host: string; readonly login: st
 
 // github.com is the overwhelmingly common host, so hide it to keep the label
 // short; surface the host only for GitHub Enterprise / self-hosted accounts.
-function githubAccountLabel(account: {
-  readonly host: string;
-  readonly login: string;
-}): string {
+function githubAccountLabel(account: { readonly host: string; readonly login: string }): string {
   return account.host === "github.com" ? account.login : `${account.login} · ${account.host}`;
 }
 
@@ -1038,10 +1037,7 @@ function ProjectGitHubAccountField({
   onSelect,
 }: {
   readonly member: SidebarProjectGroupMember;
-  readonly onSelect: (
-    member: SidebarProjectGroupMember,
-    account: GitHubAccountRef | null,
-  ) => void;
+  readonly onSelect: (member: SidebarProjectGroupMember, account: GitHubAccountRef | null) => void;
 }) {
   const discovery = useEnvironmentQuery(
     sourceControlEnvironment.discovery({ environmentId: member.environmentId, input: {} }),
@@ -1469,6 +1465,26 @@ export default function SidebarV2() {
     [updateProject],
   );
 
+  const updateProjectDefaultModelSelection = useCallback(
+    async (member: SidebarProjectGroupMember, selection: ModelSelection | null) => {
+      const result = await updateProject({
+        environmentId: member.environmentId,
+        input: { projectId: member.id, defaultModelSelection: selection },
+      });
+      if (result._tag === "Failure" && !isAtomCommandInterrupted(result)) {
+        const error = squashAtomCommandFailure(result);
+        toastManager.add(
+          stackedThreadToast({
+            type: "error",
+            title: "Failed to update project agent",
+            description: error instanceof Error ? error.message : "An error occurred.",
+          }),
+        );
+      }
+    },
+    [updateProject],
+  );
+
   const updateProjectGitHubAccount = useCallback(
     async (member: SidebarProjectGroupMember, account: GitHubAccountRef | null) => {
       const current = member.gitHubAccount;
@@ -2843,6 +2859,14 @@ export default function SidebarV2() {
                       onSelect={updateProjectGitHubAccount}
                     />
                   </div>
+                  <ProjectDefaultAgentField
+                    idPrefix={`project-agent-${member.physicalProjectKey}`}
+                    environmentId={member.environmentId}
+                    projectId={member.id}
+                    onChange={(selection) => {
+                      void updateProjectDefaultModelSelection(member, selection);
+                    }}
+                  />
                   {projectActionsTarget.memberProjects.length > 1 ? (
                     <div className="flex justify-end">
                       <Button