diff --git a/apps/mobile/src/features/archive/archivedThreadList.test.ts b/apps/mobile/src/features/archive/archivedThreadList.test.ts
index 5a1ae8d092f8..e305a8941371 100644
--- a/apps/mobile/src/features/archive/archivedThreadList.test.ts
+++ b/apps/mobile/src/features/archive/archivedThreadList.test.ts
@@ -15,6 +15,7 @@ function makeProject(
     repositoryIdentity: null,
     defaultModelSelection: null,
     gitHubAccount: null,
+    worktreeBranchPrefix: null,
     scripts: [],
     createdAt: "2026-06-01T00:00:00.000Z",
     updatedAt: "2026-06-01T00:00:00.000Z",
diff --git a/apps/mobile/src/features/home/homeListItems.test.ts b/apps/mobile/src/features/home/homeListItems.test.ts
index 13c9c323623b..6d932b90306e 100644
--- a/apps/mobile/src/features/home/homeListItems.test.ts
+++ b/apps/mobile/src/features/home/homeListItems.test.ts
@@ -27,6 +27,7 @@ function makeProject(id: string, title: string): EnvironmentProject {
     repositoryIdentity: null,
     defaultModelSelection: null,
     gitHubAccount: null,
+    worktreeBranchPrefix: null,
     scripts: [],
     createdAt: "2026-06-01T00:00:00.000Z",
     updatedAt: "2026-06-01T00:00:00.000Z",
diff --git a/apps/mobile/src/features/home/homeThreadList.test.ts b/apps/mobile/src/features/home/homeThreadList.test.ts
index 1dc983230e0f..a2f2f9f29223 100644
--- a/apps/mobile/src/features/home/homeThreadList.test.ts
+++ b/apps/mobile/src/features/home/homeThreadList.test.ts
@@ -19,6 +19,7 @@ function makeProject(
     repositoryIdentity: null,
     defaultModelSelection: null,
     gitHubAccount: null,
+    worktreeBranchPrefix: null,
     scripts: [],
     createdAt: "2026-06-01T00:00:00.000Z",
     updatedAt: "2026-06-01T00:00:00.000Z",
diff --git a/apps/mobile/src/features/home/homeThreadList.ts b/apps/mobile/src/features/home/homeThreadList.ts
index d8303ace8f29..7ac1333fc034 100644
--- a/apps/mobile/src/features/home/homeThreadList.ts
+++ b/apps/mobile/src/features/home/homeThreadList.ts
@@ -307,6 +307,7 @@ export function buildHomeThreadGroups(input: {
             repositoryIdentity: null,
             defaultModelSelection: null,
             gitHubAccount: null,
+            worktreeBranchPrefix: null,
             scripts: [],
             createdAt: pendingTask.message.createdAt,
             updatedAt: pendingTask.message.createdAt,
diff --git a/apps/mobile/src/features/showcase/showcasePendingTasks.test.ts b/apps/mobile/src/features/showcase/showcasePendingTasks.test.ts
index 178db10dc5e9..12838f6afc6b 100644
--- a/apps/mobile/src/features/showcase/showcasePendingTasks.test.ts
+++ b/apps/mobile/src/features/showcase/showcasePendingTasks.test.ts
@@ -16,6 +16,7 @@ const projects: ReadonlyArray<EnvironmentProject> = [
     repositoryIdentity: null,
     defaultModelSelection: { instanceId: ProviderInstanceId.make("codex"), model: "gpt-5.4" },
     gitHubAccount: null,
+    worktreeBranchPrefix: null,
     scripts: [],
     createdAt: "2026-07-16T08:00:00.000Z",
     updatedAt: "2026-07-16T08:00:00.000Z",
@@ -28,6 +29,7 @@ const projects: ReadonlyArray<EnvironmentProject> = [
     repositoryIdentity: null,
     defaultModelSelection: null,
     gitHubAccount: null,
+    worktreeBranchPrefix: null,
     scripts: [],
     createdAt: "2026-07-16T08:00:00.000Z",
     updatedAt: "2026-07-16T08:00:00.000Z",
diff --git a/apps/mobile/src/features/threads/new-task-flow-provider.tsx b/apps/mobile/src/features/threads/new-task-flow-provider.tsx
index 7d2375dd05a3..c6996b1a28c4 100644
--- a/apps/mobile/src/features/threads/new-task-flow-provider.tsx
+++ b/apps/mobile/src/features/threads/new-task-flow-provider.tsx
@@ -261,6 +261,7 @@ export function NewTaskFlowProvider(props: React.PropsWithChildren) {
       repositoryIdentity: null,
       defaultModelSelection: editingPendingTask.modelSelection ?? null,
       gitHubAccount: null,
+      worktreeBranchPrefix: null,
       scripts: [],
       createdAt: editingPendingTask.createdAt,
       updatedAt: editingPendingTask.createdAt,
diff --git a/apps/mobile/src/features/threads/use-project-actions.ts b/apps/mobile/src/features/threads/use-project-actions.ts
index 9d03dde59a93..d048a77c4fe9 100644
--- a/apps/mobile/src/features/threads/use-project-actions.ts
+++ b/apps/mobile/src/features/threads/use-project-actions.ts
@@ -74,7 +74,10 @@ export function useCreateProjectThread() {
           branch: input.branch,
           worktreePath: input.worktreePath,
           startFromOrigin: input.startFromOrigin ?? false,
-          worktreeBranchName: buildTemporaryWorktreeBranchName(randomHex),
+          worktreeBranchName: buildTemporaryWorktreeBranchName(
+            randomHex,
+            input.project.worktreeBranchPrefix,
+          ),
         }),
       });
       if (AsyncResult.isFailure(result)) {
diff --git a/apps/mobile/src/lib/repositoryGroups.test.ts b/apps/mobile/src/lib/repositoryGroups.test.ts
index e801571589a3..26d43f0d861c 100644
--- a/apps/mobile/src/lib/repositoryGroups.test.ts
+++ b/apps/mobile/src/lib/repositoryGroups.test.ts
@@ -13,6 +13,7 @@ function makeProject(
     repositoryIdentity: null,
     defaultModelSelection: null,
     gitHubAccount: null,
+    worktreeBranchPrefix: null,
     scripts: [],
     createdAt: "2026-04-01T00:00:00.000Z",
     updatedAt: "2026-04-01T00:00:00.000Z",
diff --git a/apps/mobile/src/state/use-thread-outbox-drain.ts b/apps/mobile/src/state/use-thread-outbox-drain.ts
index 3559fa140fe8..b27413a76cf1 100644
--- a/apps/mobile/src/state/use-thread-outbox-drain.ts
+++ b/apps/mobile/src/state/use-thread-outbox-drain.ts
@@ -270,6 +270,9 @@ export function useThreadOutboxDrain(): void {
           branch: creation.branch,
           worktreePath: creation.worktreePath,
           startFromOrigin: creation.startFromOrigin ?? false,
+          // Queued creations don't carry the project's prefix; this is only the
+          // temporary branch, which the server renames to the project's
+          // configured `<prefix>/<slug>` on the first turn.
           worktreeBranchName: buildTemporaryWorktreeBranchName(randomHex),
         }),
       });
diff --git a/apps/server/src/orchestration/Layers/OrchestrationEngine.test.ts b/apps/server/src/orchestration/Layers/OrchestrationEngine.test.ts
index c7dcefaf84f7..552f0b90e1ee 100644
--- a/apps/server/src/orchestration/Layers/OrchestrationEngine.test.ts
+++ b/apps/server/src/orchestration/Layers/OrchestrationEngine.test.ts
@@ -124,6 +124,7 @@ describe("OrchestrationEngine", () => {
             model: "gpt-5-codex",
           },
           gitHubAccount: null,
+          worktreeBranchPrefix: null,
           scripts: [],
           createdAt: "2026-03-03T00:00:00.000Z",
           updatedAt: "2026-03-03T00:00:01.000Z",
diff --git a/apps/server/src/orchestration/Layers/ProjectionPipeline.ts b/apps/server/src/orchestration/Layers/ProjectionPipeline.ts
index 11d6188fd98e..2aa9dba7b9d4 100644
--- a/apps/server/src/orchestration/Layers/ProjectionPipeline.ts
+++ b/apps/server/src/orchestration/Layers/ProjectionPipeline.ts
@@ -496,6 +496,7 @@ const makeOrchestrationProjectionPipeline = Effect.fn("makeOrchestrationProjecti
             workspaceRoot: event.payload.workspaceRoot,
             defaultModelSelection: event.payload.defaultModelSelection,
             gitHubAccount: event.payload.gitHubAccount ?? null,
+            worktreeBranchPrefix: event.payload.worktreeBranchPrefix ?? null,
             scripts: event.payload.scripts,
             createdAt: event.payload.createdAt,
             updatedAt: event.payload.updatedAt,
@@ -522,6 +523,9 @@ const makeOrchestrationProjectionPipeline = Effect.fn("makeOrchestrationProjecti
             ...(event.payload.gitHubAccount !== undefined
               ? { gitHubAccount: event.payload.gitHubAccount }
               : {}),
+            ...(event.payload.worktreeBranchPrefix !== undefined
+              ? { worktreeBranchPrefix: event.payload.worktreeBranchPrefix }
+              : {}),
             ...(event.payload.scripts !== undefined ? { scripts: event.payload.scripts } : {}),
             updatedAt: event.payload.updatedAt,
           });
diff --git a/apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.test.ts b/apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.test.ts
index c96084a25c25..73258edbac42 100644
--- a/apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.test.ts
+++ b/apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.test.ts
@@ -267,6 +267,7 @@ projectionSnapshotLayer("ProjectionSnapshotQuery", (it) => {
             model: "gpt-5-codex",
           },
           gitHubAccount: null,
+          worktreeBranchPrefix: null,
           scripts: [
             {
               id: "script-1",
@@ -383,6 +384,7 @@ projectionSnapshotLayer("ProjectionSnapshotQuery", (it) => {
             model: "gpt-5-codex",
           },
           gitHubAccount: null,
+          worktreeBranchPrefix: null,
           scripts: [
             {
               id: "script-1",
diff --git a/apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.ts b/apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.ts
index 4784d2883df0..f681e42b1488 100644
--- a/apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.ts
+++ b/apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.ts
@@ -237,6 +237,7 @@ function mapProjectShellRow(
     repositoryIdentity,
     defaultModelSelection: row.defaultModelSelection,
     gitHubAccount: row.gitHubAccount,
+    worktreeBranchPrefix: row.worktreeBranchPrefix,
     scripts: row.scripts,
     createdAt: row.createdAt,
     updatedAt: row.updatedAt,
@@ -311,6 +312,7 @@ const makeProjectionSnapshotQuery = Effect.gen(function* () {
           workspace_root AS "workspaceRoot",
           default_model_selection_json AS "defaultModelSelection",
           github_account_json AS "gitHubAccount",
+          worktree_branch_prefix AS "worktreeBranchPrefix",
           scripts_json AS "scripts",
           created_at AS "createdAt",
           updated_at AS "updatedAt",
@@ -685,6 +687,7 @@ const makeProjectionSnapshotQuery = Effect.gen(function* () {
           workspace_root AS "workspaceRoot",
           default_model_selection_json AS "defaultModelSelection",
           github_account_json AS "gitHubAccount",
+          worktree_branch_prefix AS "worktreeBranchPrefix",
           scripts_json AS "scripts",
           created_at AS "createdAt",
           updated_at AS "updatedAt",
@@ -708,6 +711,7 @@ const makeProjectionSnapshotQuery = Effect.gen(function* () {
           workspace_root AS "workspaceRoot",
           default_model_selection_json AS "defaultModelSelection",
           github_account_json AS "gitHubAccount",
+          worktree_branch_prefix AS "worktreeBranchPrefix",
           scripts_json AS "scripts",
           created_at AS "createdAt",
           updated_at AS "updatedAt",
@@ -1190,6 +1194,7 @@ const makeProjectionSnapshotQuery = Effect.gen(function* () {
                 repositoryIdentity: repositoryIdentities.get(row.projectId) ?? null,
                 defaultModelSelection: row.defaultModelSelection,
                 gitHubAccount: row.gitHubAccount,
+                worktreeBranchPrefix: row.worktreeBranchPrefix,
                 scripts: row.scripts,
                 createdAt: row.createdAt,
                 updatedAt: row.updatedAt,
@@ -1317,6 +1322,7 @@ const makeProjectionSnapshotQuery = Effect.gen(function* () {
                   workspaceRoot: row.workspaceRoot,
                   defaultModelSelection: row.defaultModelSelection,
                   gitHubAccount: row.gitHubAccount,
+                  worktreeBranchPrefix: row.worktreeBranchPrefix,
                   scripts: row.scripts,
                   createdAt: row.createdAt,
                   updatedAt: row.updatedAt,
@@ -1766,6 +1772,7 @@ const makeProjectionSnapshotQuery = Effect.gen(function* () {
                     repositoryIdentity,
                     defaultModelSelection: option.value.defaultModelSelection,
                     gitHubAccount: option.value.gitHubAccount,
+                    worktreeBranchPrefix: option.value.worktreeBranchPrefix,
                     scripts: option.value.scripts,
                     createdAt: option.value.createdAt,
                     updatedAt: option.value.updatedAt,
diff --git a/apps/server/src/orchestration/Layers/ProviderCommandReactor.ts b/apps/server/src/orchestration/Layers/ProviderCommandReactor.ts
index 3044cc6029d8..78e82acc0882 100644
--- a/apps/server/src/orchestration/Layers/ProviderCommandReactor.ts
+++ b/apps/server/src/orchestration/Layers/ProviderCommandReactor.ts
@@ -12,7 +12,7 @@ import {
   type RuntimeMode,
   type TurnId,
 } from "@t3tools/contracts";
-import { isTemporaryWorktreeBranch, WORKTREE_BRANCH_PREFIX } from "@t3tools/shared/git";
+import { isTemporaryWorktreeBranch, sanitizeWorktreeBranchPrefix } from "@t3tools/shared/git";
 import * as Cache from "effect/Cache";
 import * as Cause from "effect/Cause";
 import * as Crypto from "effect/Crypto";
@@ -166,15 +166,16 @@ function stalePendingRequestDetail(
   return `Stale pending ${requestKind} request: ${requestId}. Provider callback state does not survive app restarts or recovered sessions. Restart the turn to continue.`;
 }
 
-function buildGeneratedWorktreeBranchName(raw: string): string {
+function buildGeneratedWorktreeBranchName(raw: string, prefix?: string | null): string {
+  const resolvedPrefix = sanitizeWorktreeBranchPrefix(prefix);
   const normalized = raw
     .trim()
     .toLowerCase()
     .replace(/^refs\/heads\//, "")
     .replace(/['"`]/g, "");
 
-  const withoutPrefix = normalized.startsWith(`${WORKTREE_BRANCH_PREFIX}/`)
-    ? normalized.slice(`${WORKTREE_BRANCH_PREFIX}/`.length)
+  const withoutPrefix = normalized.startsWith(`${resolvedPrefix}/`)
+    ? normalized.slice(`${resolvedPrefix}/`.length)
     : normalized;
 
   const branchFragment = withoutPrefix
@@ -186,7 +187,7 @@ function buildGeneratedWorktreeBranchName(raw: string): string {
     .replace(/[./_-]+$/g, "");
 
   const safeFragment = branchFragment.length > 0 ? branchFragment : "update";
-  return `${WORKTREE_BRANCH_PREFIX}/${safeFragment}`;
+  return `${resolvedPrefix}/${safeFragment}`;
 }
 
 const make = Effect.gen(function* () {
@@ -677,6 +678,7 @@ const make = Effect.gen(function* () {
     readonly threadId: ThreadId;
     readonly branch: string | null;
     readonly worktreePath: string | null;
+    readonly worktreeBranchPrefix?: string | null;
     readonly messageText: string;
     readonly attachments?: ReadonlyArray<ChatAttachment>;
   }) {
@@ -708,7 +710,10 @@ const make = Effect.gen(function* () {
       });
       if (!generated) return;
 
-      const targetBranch = buildGeneratedWorktreeBranchName(generated.branch);
+      // Prefer the project's prefix, then the global default setting; an empty
+      // string or null resolves to the built-in default inside the builder.
+      const effectivePrefix = input.worktreeBranchPrefix ?? settings.worktreeBranchPrefix;
+      const targetBranch = buildGeneratedWorktreeBranchName(generated.branch, effectivePrefix);
       if (targetBranch === oldBranch) return;
 
       const renamed = yield* gitWorkflow.renameBranch({ cwd, oldBranch, newBranch: targetBranch });
@@ -822,6 +827,7 @@ const make = Effect.gen(function* () {
         threadId: event.payload.threadId,
         branch: thread.branch,
         worktreePath: thread.worktreePath,
+        worktreeBranchPrefix: project?.worktreeBranchPrefix ?? null,
         ...generationInput,
       }).pipe(Effect.forkScoped);
 
diff --git a/apps/server/src/orchestration/commandInvariants.test.ts b/apps/server/src/orchestration/commandInvariants.test.ts
index 824930ded3a4..2825a5115d48 100644
--- a/apps/server/src/orchestration/commandInvariants.test.ts
+++ b/apps/server/src/orchestration/commandInvariants.test.ts
@@ -36,6 +36,7 @@ const readModel: OrchestrationReadModel = {
         model: "gpt-5-codex",
       },
       gitHubAccount: null,
+      worktreeBranchPrefix: null,
       scripts: [],
       createdAt: now,
       updatedAt: now,
@@ -50,6 +51,7 @@ const readModel: OrchestrationReadModel = {
         model: "gpt-5-codex",
       },
       gitHubAccount: null,
+      worktreeBranchPrefix: null,
       scripts: [],
       createdAt: now,
       updatedAt: now,
diff --git a/apps/server/src/orchestration/decider.ts b/apps/server/src/orchestration/decider.ts
index 16d02496d65f..82be7530295a 100644
--- a/apps/server/src/orchestration/decider.ts
+++ b/apps/server/src/orchestration/decider.ts
@@ -251,6 +251,7 @@ export const decideOrchestrationCommand = Effect.fn("decideOrchestrationCommand"
           workspaceRoot: command.workspaceRoot,
           defaultModelSelection: command.defaultModelSelection ?? null,
           gitHubAccount: command.gitHubAccount ?? null,
+          worktreeBranchPrefix: command.worktreeBranchPrefix ?? null,
           scripts: [],
           createdAt: command.createdAt,
           updatedAt: command.createdAt,
@@ -289,6 +290,9 @@ export const decideOrchestrationCommand = Effect.fn("decideOrchestrationCommand"
             ? { defaultModelSelection: command.defaultModelSelection }
             : {}),
           ...(command.gitHubAccount !== undefined ? { gitHubAccount: command.gitHubAccount } : {}),
+          ...(command.worktreeBranchPrefix !== undefined
+            ? { worktreeBranchPrefix: command.worktreeBranchPrefix }
+            : {}),
           ...(command.scripts !== undefined ? { scripts: command.scripts } : {}),
           updatedAt: occurredAt,
         },
diff --git a/apps/server/src/orchestration/projector.ts b/apps/server/src/orchestration/projector.ts
index 1fe96dec0459..22010cf654d1 100644
--- a/apps/server/src/orchestration/projector.ts
+++ b/apps/server/src/orchestration/projector.ts
@@ -212,6 +212,7 @@ export function projectEvent(
             workspaceRoot: payload.workspaceRoot,
             defaultModelSelection: payload.defaultModelSelection,
             gitHubAccount: payload.gitHubAccount ?? null,
+            worktreeBranchPrefix: payload.worktreeBranchPrefix ?? null,
             scripts: payload.scripts,
             createdAt: payload.createdAt,
             updatedAt: payload.updatedAt,
@@ -247,6 +248,9 @@ export function projectEvent(
                   ...(payload.gitHubAccount !== undefined
                     ? { gitHubAccount: payload.gitHubAccount }
                     : {}),
+                  ...(payload.worktreeBranchPrefix !== undefined
+                    ? { worktreeBranchPrefix: payload.worktreeBranchPrefix }
+                    : {}),
                   ...(payload.scripts !== undefined ? { scripts: payload.scripts } : {}),
                   updatedAt: payload.updatedAt,
                 }
diff --git a/apps/server/src/persistence/Layers/ProjectionProjects.ts b/apps/server/src/persistence/Layers/ProjectionProjects.ts
index d5667dd33e9c..84838eabe486 100644
--- a/apps/server/src/persistence/Layers/ProjectionProjects.ts
+++ b/apps/server/src/persistence/Layers/ProjectionProjects.ts
@@ -37,6 +37,7 @@ const makeProjectionProjectRepository = Effect.gen(function* () {
           workspace_root,
           default_model_selection_json,
           github_account_json,
+          worktree_branch_prefix,
           scripts_json,
           created_at,
           updated_at,
@@ -48,6 +49,7 @@ const makeProjectionProjectRepository = Effect.gen(function* () {
           ${row.workspaceRoot},
           ${row.defaultModelSelection !== null ? JSON.stringify(row.defaultModelSelection) : null},
           ${row.gitHubAccount !== null ? JSON.stringify(row.gitHubAccount) : null},
+          ${row.worktreeBranchPrefix},
           ${JSON.stringify(row.scripts)},
           ${row.createdAt},
           ${row.updatedAt},
@@ -59,6 +61,7 @@ const makeProjectionProjectRepository = Effect.gen(function* () {
           workspace_root = excluded.workspace_root,
           default_model_selection_json = excluded.default_model_selection_json,
           github_account_json = excluded.github_account_json,
+          worktree_branch_prefix = excluded.worktree_branch_prefix,
           scripts_json = excluded.scripts_json,
           created_at = excluded.created_at,
           updated_at = excluded.updated_at,
@@ -77,6 +80,7 @@ const makeProjectionProjectRepository = Effect.gen(function* () {
           workspace_root AS "workspaceRoot",
           default_model_selection_json AS "defaultModelSelection",
           github_account_json AS "gitHubAccount",
+          worktree_branch_prefix AS "worktreeBranchPrefix",
           scripts_json AS "scripts",
           created_at AS "createdAt",
           updated_at AS "updatedAt",
@@ -97,6 +101,7 @@ const makeProjectionProjectRepository = Effect.gen(function* () {
           workspace_root AS "workspaceRoot",
           default_model_selection_json AS "defaultModelSelection",
           github_account_json AS "gitHubAccount",
+          worktree_branch_prefix AS "worktreeBranchPrefix",
           scripts_json AS "scripts",
           created_at AS "createdAt",
           updated_at AS "updatedAt",
diff --git a/apps/server/src/persistence/Layers/ProjectionRepositories.test.ts b/apps/server/src/persistence/Layers/ProjectionRepositories.test.ts
index 135af03237d1..5e06871e208f 100644
--- a/apps/server/src/persistence/Layers/ProjectionRepositories.test.ts
+++ b/apps/server/src/persistence/Layers/ProjectionRepositories.test.ts
@@ -34,6 +34,7 @@ projectionRepositoriesLayer("Projection repositories", (it) => {
           model: "gpt-5.4",
         },
         gitHubAccount: null,
+        worktreeBranchPrefix: null,
         scripts: [],
         createdAt: "2026-03-24T00:00:00.000Z",
         updatedAt: "2026-03-24T00:00:00.000Z",
diff --git a/apps/server/src/persistence/Migrations.ts b/apps/server/src/persistence/Migrations.ts
index 02ea71010715..a612e4e51b48 100644
--- a/apps/server/src/persistence/Migrations.ts
+++ b/apps/server/src/persistence/Migrations.ts
@@ -48,6 +48,7 @@ import Migration0032 from "./Migrations/032_AuthPairingProofKeyThumbprint.ts";
 import Migration0033 from "./Migrations/033_ProjectionThreadsSettled.ts";
 import Migration0034 from "./Migrations/034_ProjectionThreadsSnoozed.ts";
 import Migration0035 from "./Migrations/035_ProjectionProjectsGitHubAccount.ts";
+import Migration0036 from "./Migrations/036_ProjectionProjectsWorktreeBranchPrefix.ts";
 
 /**
  * Migration loader with all migrations defined inline.
@@ -95,6 +96,7 @@ export const migrationEntries = [
   [33, "ProjectionThreadsSettled", Migration0033],
   [34, "ProjectionThreadsSnoozed", Migration0034],
   [35, "ProjectionProjectsGitHubAccount", Migration0035],
+  [36, "ProjectionProjectsWorktreeBranchPrefix", Migration0036],
 ] as const;
 
 export const makeMigrationLoader = (throughId?: number) =>
diff --git a/apps/server/src/persistence/Migrations/036_ProjectionProjectsWorktreeBranchPrefix.ts b/apps/server/src/persistence/Migrations/036_ProjectionProjectsWorktreeBranchPrefix.ts
new file mode 100644
index 000000000000..81a36d476c17
--- /dev/null
+++ b/apps/server/src/persistence/Migrations/036_ProjectionProjectsWorktreeBranchPrefix.ts
@@ -0,0 +1,16 @@
+import * as Effect from "effect/Effect";
+import * as SqlClient from "effect/unstable/sql/SqlClient";
+
+export default Effect.gen(function* () {
+  const sql = yield* SqlClient.SqlClient;
+  const columns = yield* sql<{ readonly name: string }>`
+    PRAGMA table_info(projection_projects)
+  `;
+
+  if (!columns.some((column) => column.name === "worktree_branch_prefix")) {
+    yield* sql`
+      ALTER TABLE projection_projects
+      ADD COLUMN worktree_branch_prefix TEXT
+    `;
+  }
+});
diff --git a/apps/server/src/persistence/Services/ProjectionProjects.ts b/apps/server/src/persistence/Services/ProjectionProjects.ts
index 7fd5332ad124..5a9129ab9113 100644
--- a/apps/server/src/persistence/Services/ProjectionProjects.ts
+++ b/apps/server/src/persistence/Services/ProjectionProjects.ts
@@ -26,6 +26,7 @@ export const ProjectionProject = Schema.Struct({
   workspaceRoot: Schema.String,
   defaultModelSelection: Schema.NullOr(ModelSelection),
   gitHubAccount: Schema.NullOr(GitHubAccountRef),
+  worktreeBranchPrefix: Schema.NullOr(Schema.String),
   scripts: Schema.Array(ProjectScript),
   createdAt: IsoDateTime,
   updatedAt: IsoDateTime,
diff --git a/apps/server/src/project/ProjectSetupScriptRunner.test.ts b/apps/server/src/project/ProjectSetupScriptRunner.test.ts
index e22f3bc92dd8..fcd66d2becbb 100644
--- a/apps/server/src/project/ProjectSetupScriptRunner.test.ts
+++ b/apps/server/src/project/ProjectSetupScriptRunner.test.ts
@@ -19,6 +19,7 @@ const makeProject = (scripts: OrchestrationProject["scripts"]): OrchestrationPro
   workspaceRoot: "/repo/project",
   defaultModelSelection: null,
   gitHubAccount: null,
+  worktreeBranchPrefix: null,
   scripts,
   createdAt: "2026-01-01T00:00:00.000Z",
   updatedAt: "2026-01-01T00:00:00.000Z",
diff --git a/apps/server/src/relay/AgentAwarenessRelay.test.ts b/apps/server/src/relay/AgentAwarenessRelay.test.ts
index b186e9b8a007..a0c2d86d74ee 100644
--- a/apps/server/src/relay/AgentAwarenessRelay.test.ts
+++ b/apps/server/src/relay/AgentAwarenessRelay.test.ts
@@ -429,6 +429,7 @@ describe.sequential("signRelayAgentActivityPublishProof", () => {
           repositoryIdentity: null,
           defaultModelSelection: null,
           gitHubAccount: null,
+          worktreeBranchPrefix: null,
           scripts: [],
           createdAt: now,
           updatedAt: now,
@@ -588,6 +589,7 @@ describe.sequential("signRelayAgentActivityPublishProof", () => {
           repositoryIdentity: null,
           defaultModelSelection: null,
           gitHubAccount: null,
+          worktreeBranchPrefix: null,
           scripts: [],
           createdAt: now,
           updatedAt: now,
diff --git a/apps/server/src/server.test.ts b/apps/server/src/server.test.ts
index 12b01784d2c4..7cdab76dd074 100644
--- a/apps/server/src/server.test.ts
+++ b/apps/server/src/server.test.ts
@@ -154,6 +154,7 @@ const makeDefaultOrchestrationReadModel = () => {
         workspaceRoot: "/tmp/default-project",
         defaultModelSelection,
         gitHubAccount: null,
+        worktreeBranchPrefix: null,
         scripts: [],
         createdAt: now,
         updatedAt: now,
@@ -5689,6 +5690,7 @@ it.layer(NodeServices.layer)("server router seam", (it) => {
             workspaceRoot: "/tmp/project-a",
             defaultModelSelection,
             gitHubAccount: null,
+            worktreeBranchPrefix: null,
             scripts: [],
             createdAt: now,
             updatedAt: now,
diff --git a/apps/server/src/serverRuntimeStartup.test.ts b/apps/server/src/serverRuntimeStartup.test.ts
index 6777daae5b13..220a9fdeedb0 100644
--- a/apps/server/src/serverRuntimeStartup.test.ts
+++ b/apps/server/src/serverRuntimeStartup.test.ts
@@ -148,6 +148,7 @@ it.effect("resolveAutoBootstrapWelcomeTargets returns existing project and threa
               workspaceRoot: "/tmp/startup-project",
               defaultModelSelection: ServerRuntimeStartup.getAutoBootstrapDefaultModelSelection(),
               gitHubAccount: null,
+              worktreeBranchPrefix: null,
               scripts: [],
               createdAt: "2026-01-01T00:00:00.000Z",
               updatedAt: "2026-01-01T00:00:00.000Z",
diff --git a/apps/server/src/sourceControl/GitHubAccountResolver.ts b/apps/server/src/sourceControl/GitHubAccountResolver.ts
index 16dfe50e66ca..8d297fcab65b 100644
--- a/apps/server/src/sourceControl/GitHubAccountResolver.ts
+++ b/apps/server/src/sourceControl/GitHubAccountResolver.ts
@@ -65,6 +65,32 @@ export function gitHubAccountGhEnv(resolved: ResolvedGitHubAccount): NodeJS.Proc
   };
 }
 
+/**
+ * Environment that makes BOTH `gh` and plain `git` (push/fetch over HTTPS) act
+ * as `resolved`'s account, for a single process (e.g. an interactive terminal
+ * or a one-off git command) — without touching global config or running
+ * `gh auth switch`.
+ *
+ * On top of {@link gitHubAccountGhEnv} (which points `gh` at the account via
+ * `GH_TOKEN`/`GH_ENTERPRISE_TOKEN` + `GH_HOST`), this wires git's credential
+ * helper to GitHub CLI via `GIT_CONFIG_*` env keys — equivalent to
+ * `gh auth setup-git` but scoped to this process only. The leading empty helper
+ * resets any inherited helper (OS keychain, global config) so the selected
+ * account wins; `!gh auth git-credential` then returns the `GH_TOKEN` above.
+ * This is the same mechanism CI uses (`GH_TOKEN` + gh credential helper).
+ */
+export function gitHubAccountAuthEnv(resolved: ResolvedGitHubAccount): NodeJS.ProcessEnv {
+  const baseUrl = `https://${resolved.account.host}`;
+  return {
+    ...gitHubAccountGhEnv(resolved),
+    GIT_CONFIG_COUNT: "2",
+    GIT_CONFIG_KEY_0: `credential.${baseUrl}.helper`,
+    GIT_CONFIG_VALUE_0: "",
+    GIT_CONFIG_KEY_1: `credential.${baseUrl}.helper`,
+    GIT_CONFIG_VALUE_1: "!gh auth git-credential",
+  };
+}
+
 /**
  * True when `cwd` is `base` itself or lives beneath it. Compares normalized,
  * separator-terminated paths so `/a/repo` does not match `/a/repo-2`.
diff --git a/apps/server/src/sourceControl/GitHubSourceControlProvider.test.ts b/apps/server/src/sourceControl/GitHubSourceControlProvider.test.ts
index 9e8a68295667..dec121a5b2d5 100644
--- a/apps/server/src/sourceControl/GitHubSourceControlProvider.test.ts
+++ b/apps/server/src/sourceControl/GitHubSourceControlProvider.test.ts
@@ -207,33 +207,22 @@ it.effect("creates GitHub PRs through provider-neutral input names", () =>
   }),
 );
 
+const GH_AUTH_STATUS_ACTIVE_PLUS_STALE = `github.com
+  ✓ Logged in to github.com account active-user (keyring)
+  - Active account: true
+  - Git operations protocol: ssh
+  - Token: gho_************************************
+  - Token scopes: 'gist', 'read:org', 'repo'
+
+  X Failed to log in to github.com account stale-user (keyring)
+  - The token in keyring is invalid.
+  - To re-authenticate, run: gh auth login -h github.com
+  - To forget about this account, run: gh auth logout -h github.com -u stale-user
+`;
+
 it("accepts active authenticated GitHub accounts when another account fails", () => {
   const auth = GitHubSourceControlProvider.discovery.parseAuth(
-    processResult(
-      JSON.stringify({
-        hosts: {
-          "github.com": [
-            {
-              state: "success",
-              active: true,
-              host: "github.com",
-              login: "active-user",
-              tokenSource: "keyring",
-              gitProtocol: "ssh",
-            },
-            {
-              state: "error",
-              active: false,
-              host: "github.com",
-              login: "stale-user",
-              tokenSource: "keyring",
-              gitProtocol: "ssh",
-              error: "The token in keyring is invalid.",
-            },
-          ],
-        },
-      }),
-    ),
+    processResult(GH_AUTH_STATUS_ACTIVE_PLUS_STALE),
   );
 
   assert.deepStrictEqual(
@@ -250,25 +239,14 @@ it("accepts active authenticated GitHub accounts when another account fails", ()
   );
 });
 
-it("parses GitHub auth JSON from stdout when stderr has warnings", () => {
+it("parses GitHub auth status from stderr when stdout is empty (older gh)", () => {
   const auth = GitHubSourceControlProvider.discovery.parseAuth(
-    processResult(
-      JSON.stringify({
-        hosts: {
-          "github.com": [
-            {
-              state: "success",
-              active: true,
-              host: "github.com",
-              login: "active-user",
-              tokenSource: "keyring",
-              gitProtocol: "ssh",
-            },
-          ],
-        },
-      }),
-      { stderr: "warning: ignored diagnostic from gh\n" },
-    ),
+    processResult("", {
+      stderr: `github.com
+  ✓ Logged in to github.com account active-user (keyring)
+  - Active account: true
+`,
+    }),
   );
 
   assert.deepStrictEqual(
@@ -288,38 +266,19 @@ it("parses GitHub auth JSON from stdout when stderr has warnings", () => {
 it("parses GitHub auth status accounts by host and active state", () => {
   assert.deepStrictEqual(
     parseGitHubAuthStatus(
-      JSON.stringify({
-        hosts: {
-          "github.com": [
-            {
-              state: "success",
-              active: true,
-              host: "github.com",
-              login: "active-user",
-              tokenSource: "keyring",
-              gitProtocol: "ssh",
-            },
-            {
-              state: "error",
-              active: false,
-              host: "github.com",
-              login: "stale-user",
-              tokenSource: "keyring",
-              gitProtocol: "ssh",
-            },
-          ],
-          "github.example.test": [
-            {
-              state: "success",
-              active: false,
-              host: "github.example.test",
-              login: "enterprise-user",
-              tokenSource: "keyring",
-              gitProtocol: "ssh",
-            },
-          ],
-        },
-      }),
+      `github.com
+  ✓ Logged in to github.com account active-user (keyring)
+  - Active account: true
+  - Git operations protocol: ssh
+
+  X Failed to log in to github.com account stale-user (keyring)
+  - The token in keyring is invalid.
+
+github.example.test
+  ✓ Logged in to github.example.test account enterprise-user (keyring)
+  - Active account: false
+  - Git operations protocol: ssh
+`,
     ).accounts,
     [
       {
@@ -334,7 +293,7 @@ it("parses GitHub auth status accounts by host and active state", () => {
         account: "stale-user",
         authenticated: false,
         active: false,
-        error: null,
+        error: "The token in keyring is invalid.",
       },
       {
         host: "github.example.test",
@@ -347,24 +306,15 @@ it("parses GitHub auth status accounts by host and active state", () => {
   );
 });
 
-it("reports unauthenticated when GitHub JSON has accounts but none are valid", () => {
+it("reports unauthenticated when GitHub accounts exist but none are valid", () => {
   const auth = GitHubSourceControlProvider.discovery.parseAuth(
     processResult(
-      JSON.stringify({
-        hosts: {
-          "github.com": [
-            {
-              state: "error",
-              active: true,
-              host: "github.com",
-              login: "stale-user",
-              tokenSource: "keyring",
-              gitProtocol: "ssh",
-              error: "The token in keyring is invalid.",
-            },
-          ],
-        },
-      }),
+      `github.com
+  X Failed to log in to github.com account stale-user (keyring)
+  - The token in keyring is invalid.
+  - To re-authenticate, run: gh auth login -h github.com
+`,
+      { exitCode: ChildProcessSpawner.ExitCode(1) },
     ),
   );
 
diff --git a/apps/server/src/sourceControl/GitHubSourceControlProvider.ts b/apps/server/src/sourceControl/GitHubSourceControlProvider.ts
index cfe140fea545..4d2c6611b65c 100644
--- a/apps/server/src/sourceControl/GitHubSourceControlProvider.ts
+++ b/apps/server/src/sourceControl/GitHubSourceControlProvider.ts
@@ -44,7 +44,7 @@ function toChangeRequest(summary: GitHubCli.GitHubPullRequestSummary): ChangeReq
 
 function parseGitHubAuth(input: SourceControlAuthProbeInput) {
   const output = combinedAuthOutput(input);
-  const authStatus = parseGitHubAuthStatus(input.stdout);
+  const authStatus = parseGitHubAuthStatus(output);
   const authenticatedAccount = findAuthenticatedGitHubAccount(authStatus.accounts);
   const host = authenticatedAccount?.host;
 
@@ -83,7 +83,7 @@ function parseGitHubAuth(input: SourceControlAuthProbeInput) {
 }
 
 function parseGitHubAccounts(input: SourceControlAuthProbeInput) {
-  return parseGitHubAuthStatus(input.stdout).accounts.map((account) => ({
+  return parseGitHubAuthStatus(combinedAuthOutput(input)).accounts.map((account) => ({
     host: account.host,
     login: account.account,
     authenticated: account.authenticated,
@@ -97,7 +97,7 @@ export const discovery = {
   label: "GitHub",
   executable: "gh",
   versionArgs: ["--version"],
-  authArgs: ["auth", "status", "--json", "hosts"],
+  authArgs: ["auth", "status"],
   parseAuth: parseGitHubAuth,
   parseAccounts: parseGitHubAccounts,
   installHint:
diff --git a/apps/server/src/sourceControl/SourceControlDiscovery.test.ts b/apps/server/src/sourceControl/SourceControlDiscovery.test.ts
index 9e4702af04cd..71396db99737 100644
--- a/apps/server/src/sourceControl/SourceControlDiscovery.test.ts
+++ b/apps/server/src/sourceControl/SourceControlDiscovery.test.ts
@@ -59,24 +59,13 @@ it.effect("reports implemented tools separately from locally available executabl
       if (input.command === "gh" && input.args[0] === "--version") {
         return Effect.succeed(processOutput("gh version 2.83.0\n"));
       }
-      if (input.command === "gh" && input.args.join(" ") === "auth status --json hosts") {
+      if (input.command === "gh" && input.args.join(" ") === "auth status") {
         return Effect.succeed(
-          processOutput(
-            JSON.stringify({
-              hosts: {
-                "github.com": [
-                  {
-                    state: "success",
-                    active: true,
-                    host: "github.com",
-                    login: "juliusmarminge",
-                    tokenSource: "keyring",
-                    gitProtocol: "ssh",
-                  },
-                ],
-              },
-            }),
-          ),
+          processOutput(`github.com
+  ✓ Logged in to github.com account juliusmarminge (keyring)
+  - Active account: true
+  - Git operations protocol: ssh
+`),
         );
       }
       return Effect.fail(
@@ -175,24 +164,13 @@ it.effect("probes provider authentication without exposing token details", () =>
       if (input.args[0] === "--version") {
         return Effect.succeed(processOutput(`${input.command} version test\n`));
       }
-      if (input.command === "gh" && input.args.join(" ") === "auth status --json hosts") {
+      if (input.command === "gh" && input.args.join(" ") === "auth status") {
         return Effect.succeed(
-          processOutput(
-            JSON.stringify({
-              hosts: {
-                "github.com": [
-                  {
-                    state: "success",
-                    active: true,
-                    host: "github.com",
-                    login: "octocat",
-                    tokenSource: "keyring",
-                    gitProtocol: "ssh",
-                  },
-                ],
-              },
-            }),
-          ),
+          processOutput(`github.com
+  ✓ Logged in to github.com account octocat (keyring)
+  - Active account: true
+  - Git operations protocol: ssh
+`),
         );
       }
       if (input.command === "glab" && input.args.join(" ") === "auth status") {
diff --git a/apps/server/src/sourceControl/gitHubAuthStatus.ts b/apps/server/src/sourceControl/gitHubAuthStatus.ts
index d58909c560c2..4e234882ff64 100644
--- a/apps/server/src/sourceControl/gitHubAuthStatus.ts
+++ b/apps/server/src/sourceControl/gitHubAuthStatus.ts
@@ -1,22 +1,3 @@
-import * as Option from "effect/Option";
-import * as Schema from "effect/Schema";
-
-const GitHubAuthStatusAccountSchema = Schema.Struct({
-  state: Schema.String,
-  error: Schema.optional(Schema.String),
-  active: Schema.Boolean,
-  host: Schema.String,
-  login: Schema.String,
-});
-
-const GitHubAuthStatusSchema = Schema.Struct({
-  hosts: Schema.Record(Schema.String, Schema.Array(GitHubAuthStatusAccountSchema)),
-});
-
-const decodeGitHubAuthStatusJson = Schema.decodeUnknownOption(
-  Schema.fromJsonString(GitHubAuthStatusSchema),
-);
-
 export interface GitHubAuthStatusAccount {
   readonly host: string;
   readonly account: string;
@@ -30,36 +11,101 @@ export interface GitHubAuthStatus {
   readonly accounts: ReadonlyArray<GitHubAuthStatusAccount>;
 }
 
+interface MutableGitHubAuthStatusAccount {
+  host: string;
+  account: string;
+  authenticated: boolean;
+  active: boolean;
+  error: string | null;
+}
+
 function nonEmptyString(value: string): string | null {
   const trimmed = value.trim();
   return trimmed.length > 0 ? trimmed : null;
 }
 
+// `gh auth status` has no `--json` flag; it only prints a human-readable
+// report. Each account is introduced by a header line and followed by
+// indented `- key: value` detail lines, e.g.:
+//
+//   github.com
+//     ✓ Logged in to github.com account octocat (keyring)
+//     - Active account: true
+//     - Git operations protocol: https
+//     - Token: gho_************************************
+//     - Token scopes: 'gist', 'read:org', 'repo'
+//
+//   X Failed to log in to github.com account stale-user (keyring)
+//     - The token in keyring is invalid.
+//     - To re-authenticate, run: gh auth login -h github.com
+//
+// We match on the stable "Logged in to" / "Failed to log in to" phrases
+// rather than the colored status glyph, which varies by terminal/version.
+const LOGGED_IN_PATTERN = /Logged in to (\S+) account (\S+)/;
+const FAILED_PATTERN = /Failed to log in to (\S+) account (\S+)/;
+const ACTIVE_ACCOUNT_PATTERN = /^-\s*Active account:\s*(true|false)/i;
+const KNOWN_DETAIL_PATTERN =
+  /^(?:Active account:|Git operations protocol:|Token(?:\s+scopes)?:|To (?:re-authenticate|forget))/i;
+
 export function parseGitHubAuthStatus(text: string): GitHubAuthStatus {
-  return Option.match(decodeGitHubAuthStatusJson(text), {
-    onNone: () => ({ parsed: false, accounts: [] }),
-    onSome: (status) =>
-      ({
-        parsed: true,
-        accounts: Object.values(status.hosts).flatMap((accounts) =>
-          accounts.flatMap((account) => {
-            const host = nonEmptyString(account.host);
-            const login = nonEmptyString(account.login);
-            if (host === null || login === null) return [];
+  const accounts: MutableGitHubAuthStatusAccount[] = [];
+  let current: MutableGitHubAuthStatusAccount | null = null;
+  let sawAccountHeader = false;
+
+  const finalize = () => {
+    if (current !== null) {
+      accounts.push(current);
+      current = null;
+    }
+  };
+
+  for (const rawLine of text.split(/\r?\n/)) {
+    const line = rawLine.trim();
+    if (line.length === 0) continue;
+
+    const loggedIn = LOGGED_IN_PATTERN.exec(line);
+    const failed = loggedIn ? null : FAILED_PATTERN.exec(line);
+    const header = loggedIn ?? failed;
+    if (header) {
+      finalize();
+      sawAccountHeader = true;
+      const host = nonEmptyString(header[1] ?? "");
+      const login = nonEmptyString(header[2] ?? "");
+      current =
+        host === null || login === null
+          ? null
+          : {
+              host: host.toLowerCase(),
+              account: login,
+              authenticated: loggedIn !== null,
+              active: false,
+              error: null,
+            };
+      continue;
+    }
+
+    if (current === null) continue;
+
+    const activeMatch = ACTIVE_ACCOUNT_PATTERN.exec(line);
+    if (activeMatch) {
+      current.active = activeMatch[1]?.toLowerCase() === "true";
+      continue;
+    }
+
+    // The first descriptive detail line under a failed account is its reason.
+    if (!current.authenticated && current.error === null && line.startsWith("-")) {
+      const detail = line.replace(/^-\s*/, "").trim();
+      if (detail.length > 0 && !KNOWN_DETAIL_PATTERN.test(detail)) {
+        current.error = detail;
+      }
+    }
+  }
+  finalize();
 
-            return [
-              {
-                host: host.toLowerCase(),
-                account: login,
-                authenticated: account.state === "success",
-                active: account.active,
-                error: account.error?.trim() || null,
-              },
-            ];
-          }),
-        ),
-      }) satisfies GitHubAuthStatus,
-  });
+  return {
+    parsed: sawAccountHeader,
+    accounts: accounts.map((account) => ({ ...account })),
+  };
 }
 
 export function findAuthenticatedGitHubAccount(
diff --git a/apps/server/src/terminal/Manager.ts b/apps/server/src/terminal/Manager.ts
index caa5106bb9fd..33ed64f6b070 100644
--- a/apps/server/src/terminal/Manager.ts
+++ b/apps/server/src/terminal/Manager.ts
@@ -59,6 +59,10 @@ import {
 } from "../observability/Metrics.ts";
 import * as ProcessRunner from "../processRunner.ts";
 import * as PortScanner from "../preview/PortScanner.ts";
+import {
+  GitHubAccountResolver,
+  gitHubAccountAuthEnv,
+} from "../sourceControl/GitHubAccountResolver.ts";
 import * as PtyAdapter from "./PtyAdapter.ts";
 
 export {
@@ -1845,6 +1849,21 @@ export const makeWithOptions = Effect.fn("TerminalManager.makeWithOptions")(func
     return yield* trySpawn(shellCandidates, spawnEnv, session, index + 1, spawnError);
   });
 
+  /**
+   * Env that makes `gh`/`git` in the spawned shell act as the GitHub account
+   * selected for the project owning `cwd`. Returns `{}` when no account is
+   * attached or the resolver isn't provided, leaving ambient auth untouched.
+   */
+  const resolveTerminalAccountEnv = (cwd: string): Effect.Effect<NodeJS.ProcessEnv> =>
+    Effect.gen(function* () {
+      const resolverOption = yield* Effect.serviceOption(GitHubAccountResolver);
+      if (Option.isNone(resolverOption)) {
+        return {};
+      }
+      const resolved = yield* resolverOption.value.resolveForCwd(cwd);
+      return resolved === null ? {} : gitHubAccountAuthEnv(resolved);
+    });
+
   const startSession = Effect.fn("terminal.startSession")(function* (
     session: TerminalSessionState,
     input: TerminalStartInput,
@@ -1885,7 +1904,15 @@ export const makeWithOptions = Effect.fn("TerminalManager.makeWithOptions")(func
           Effect.gen(function* () {
             const shellCandidates = resolveShellCandidates(shellResolver, platform, baseEnv);
             const terminalEnv = createTerminalSpawnEnv(baseEnv, session.runtimeEnv);
-            const spawnResult = yield* trySpawn(shellCandidates, terminalEnv, session);
+            // Make `gh` and `git` in this terminal act as the project's selected
+            // GitHub account (if any), so pushes/PRs use the right identity
+            // without the user running `gh auth switch`.
+            const accountEnv = yield* resolveTerminalAccountEnv(session.cwd);
+            const spawnResult = yield* trySpawn(
+              shellCandidates,
+              { ...terminalEnv, ...accountEnv },
+              session,
+            );
             ptyProcess = spawnResult.process;
             startedShell = spawnResult.shellLabel;
 
diff --git a/apps/server/src/vcs/GitVcsDriverCore.ts b/apps/server/src/vcs/GitVcsDriverCore.ts
index 3aa7575d5909..3fefd662b31b 100644
--- a/apps/server/src/vcs/GitVcsDriverCore.ts
+++ b/apps/server/src/vcs/GitVcsDriverCore.ts
@@ -35,6 +35,10 @@ import {
   parseRemoteNamesInGitOrder,
   parseRemoteRefWithRemoteNames,
 } from "../git/remoteRefs.ts";
+import {
+  GitHubAccountResolver,
+  gitHubAccountAuthEnv,
+} from "../sourceControl/GitHubAccountResolver.ts";
 import { ServerConfig } from "../config.ts";
 
 const DEFAULT_TIMEOUT_MS = 30_000;
@@ -904,6 +908,30 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
   ): Effect.Effect<void, GitCommandError> =>
     executeGit(operation, cwd, args, { allowNonZeroExit }).pipe(Effect.asVoid);
 
+  /**
+   * Resolve the env that authenticates git/gh as the project's selected GitHub
+   * account for `cwd`. Returns `{}` when no account is attached or the resolver
+   * isn't provided (tests/minimal layers), leaving ambient auth untouched.
+   */
+  const resolveAccountAuthEnv = (cwd: string): Effect.Effect<NodeJS.ProcessEnv> =>
+    Effect.gen(function* () {
+      const resolverOption = yield* Effect.serviceOption(GitHubAccountResolver);
+      if (Option.isNone(resolverOption)) {
+        return {};
+      }
+      const resolved = yield* resolverOption.value.resolveForCwd(cwd);
+      return resolved === null ? {} : gitHubAccountAuthEnv(resolved);
+    });
+
+  const runGitWithEnv = (
+    operation: string,
+    cwd: string,
+    args: readonly string[],
+    env: NodeJS.ProcessEnv,
+    allowNonZeroExit = false,
+  ): Effect.Effect<void, GitCommandError> =>
+    executeGit(operation, cwd, args, { allowNonZeroExit, env }).pipe(Effect.asVoid);
+
   const runGitStdout = (
     operation: string,
     cwd: string,
@@ -1828,15 +1856,18 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
       });
     }
 
+    // Authenticate the push as the project's selected GitHub account (if any).
+    const authEnv = yield* resolveAccountAuthEnv(cwd);
+
     const requestedRemoteName = options?.remoteName?.trim() || null;
     if (requestedRemoteName) {
       const publishBranch = yield* resolvePublishBranchName(cwd, branch);
-      yield* runGit("GitVcsDriver.pushCurrentBranch.pushWithRequestedRemote", cwd, [
-        "push",
-        "-u",
-        requestedRemoteName,
-        `HEAD:refs/heads/${publishBranch}`,
-      ]);
+      yield* runGitWithEnv(
+        "GitVcsDriver.pushCurrentBranch.pushWithRequestedRemote",
+        cwd,
+        ["push", "-u", requestedRemoteName, `HEAD:refs/heads/${publishBranch}`],
+        authEnv,
+      );
       return {
         status: "pushed" as const,
         branch,
@@ -1894,12 +1925,12 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
         });
       }
       const publishBranch = yield* resolvePublishBranchName(cwd, branch);
-      yield* runGit("GitVcsDriver.pushCurrentBranch.pushWithUpstream", cwd, [
-        "push",
-        "-u",
-        publishRemoteName,
-        `HEAD:refs/heads/${publishBranch}`,
-      ]);
+      yield* runGitWithEnv(
+        "GitVcsDriver.pushCurrentBranch.pushWithUpstream",
+        cwd,
+        ["push", "-u", publishRemoteName, `HEAD:refs/heads/${publishBranch}`],
+        authEnv,
+      );
       return {
         status: "pushed" as const,
         branch,
@@ -1912,11 +1943,12 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
       Effect.orElseSucceed(() => null),
     );
     if (currentUpstream) {
-      yield* runGit("GitVcsDriver.pushCurrentBranch.pushUpstream", cwd, [
-        "push",
-        currentUpstream.remoteName,
-        `HEAD:refs/heads/${currentUpstream.branchName}`,
-      ]);
+      yield* runGitWithEnv(
+        "GitVcsDriver.pushCurrentBranch.pushUpstream",
+        cwd,
+        ["push", currentUpstream.remoteName, `HEAD:refs/heads/${currentUpstream.branchName}`],
+        authEnv,
+      );
       return {
         status: "pushed" as const,
         branch,
@@ -1925,7 +1957,7 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
       };
     }
 
-    yield* runGit("GitVcsDriver.pushCurrentBranch.push", cwd, ["push"]);
+    yield* runGitWithEnv("GitVcsDriver.pushCurrentBranch.push", cwd, ["push"], authEnv);
     return {
       status: "pushed" as const,
       branch,
@@ -2576,12 +2608,13 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
 
   const fetchRemote: GitVcsDriver.GitVcsDriver["Service"]["fetchRemote"] = Effect.fn("fetchRemote")(
     function* (input) {
+      const authEnv = yield* resolveAccountAuthEnv(input.cwd);
       yield* executeGit(
         "GitVcsDriver.fetchRemote",
         input.cwd,
         ["fetch", "--quiet", input.remoteName],
         {
-          env: STATUS_UPSTREAM_REFRESH_ENV,
+          env: { ...STATUS_UPSTREAM_REFRESH_ENV, ...authEnv },
           fallbackErrorDetail: `git fetch ${input.remoteName} failed`,
         },
       );
@@ -2609,13 +2642,19 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
   const fetchRemoteBranch: GitVcsDriver.GitVcsDriver["Service"]["fetchRemoteBranch"] = Effect.fn(
     "fetchRemoteBranch",
   )(function* (input) {
-    yield* runGit("GitVcsDriver.fetchRemoteBranch.fetch", input.cwd, [
-      "fetch",
-      "--quiet",
-      "--no-tags",
-      input.remoteName,
-      `+refs/heads/${input.remoteBranch}:refs/remotes/${input.remoteName}/${input.remoteBranch}`,
-    ]);
+    const authEnv = yield* resolveAccountAuthEnv(input.cwd);
+    yield* runGitWithEnv(
+      "GitVcsDriver.fetchRemoteBranch.fetch",
+      input.cwd,
+      [
+        "fetch",
+        "--quiet",
+        "--no-tags",
+        input.remoteName,
+        `+refs/heads/${input.remoteBranch}:refs/remotes/${input.remoteName}/${input.remoteBranch}`,
+      ],
+      authEnv,
+    );
 
     const localBranchAlreadyExists = yield* branchExists(input.cwd, input.localBranch);
     const targetRef = `${input.remoteName}/${input.remoteBranch}`;
diff --git a/apps/server/src/ws.ts b/apps/server/src/ws.ts
index 1fa5e489a651..8e55ce11ef85 100644
--- a/apps/server/src/ws.ts
+++ b/apps/server/src/ws.ts
@@ -913,24 +913,44 @@ const makeWsRpcLayer = (
             }
 
             if (bootstrap?.prepareWorktree) {
-              let worktreeBaseRef = bootstrap.prepareWorktree.baseBranch;
-              if (bootstrap.prepareWorktree.startFromOrigin) {
-                yield* gitWorkflow.fetchRemote({
-                  cwd: bootstrap.prepareWorktree.projectCwd,
-                  remoteName: "origin",
-                });
-                const resolvedRemoteBase = yield* gitWorkflow.resolveRemoteTrackingCommit({
-                  cwd: bootstrap.prepareWorktree.projectCwd,
-                  refName: bootstrap.prepareWorktree.baseBranch,
-                  fallbackRemoteName: "origin",
-                });
-                worktreeBaseRef = resolvedRemoteBase.commitSha;
+              const prepareWorktree = bootstrap.prepareWorktree;
+              let worktreeBaseRef = prepareWorktree.baseBranch;
+              if (prepareWorktree.startFromOrigin) {
+                // Basing the new worktree on the freshest origin commit is a
+                // best-effort optimization. If origin is unreachable (offline,
+                // auth failure, no remote), `git fetch origin` errors — but that
+                // must not block getting into the worktree. Fall back to the
+                // local base branch and continue instead of failing the turn.
+                worktreeBaseRef = yield* Effect.gen(function* () {
+                  yield* gitWorkflow.fetchRemote({
+                    cwd: prepareWorktree.projectCwd,
+                    remoteName: "origin",
+                  });
+                  const resolvedRemoteBase = yield* gitWorkflow.resolveRemoteTrackingCommit({
+                    cwd: prepareWorktree.projectCwd,
+                    refName: prepareWorktree.baseBranch,
+                    fallbackRemoteName: "origin",
+                  });
+                  return resolvedRemoteBase.commitSha;
+                }).pipe(
+                  Effect.catch((error) =>
+                    Effect.logWarning(
+                      "bootstrap turn start could not start worktree from origin; using local base branch instead",
+                      {
+                        threadId: command.threadId,
+                        projectCwd: prepareWorktree.projectCwd,
+                        baseBranch: prepareWorktree.baseBranch,
+                        detail: error.message,
+                      },
+                    ).pipe(Effect.as(prepareWorktree.baseBranch)),
+                  ),
+                );
               }
               const worktree = yield* gitWorkflow.createWorktree({
-                cwd: bootstrap.prepareWorktree.projectCwd,
+                cwd: prepareWorktree.projectCwd,
                 refName: worktreeBaseRef,
-                newRefName: bootstrap.prepareWorktree.branch,
-                baseRefName: bootstrap.prepareWorktree.baseBranch,
+                newRefName: prepareWorktree.branch,
+                baseRefName: prepareWorktree.baseBranch,
                 path: null,
               });
               targetWorktreePath = worktree.worktree.path;
diff --git a/apps/web/src/components/ChatView.tsx b/apps/web/src/components/ChatView.tsx
index d532c8b1233b..370cbd5e9db6 100644
--- a/apps/web/src/components/ChatView.tsx
+++ b/apps/web/src/components/ChatView.tsx
@@ -4790,7 +4790,10 @@ function ChatViewContent(props: ChatViewProps) {
                     prepareWorktree: {
                       projectCwd: activeProject.workspaceRoot,
                       baseBranch: baseBranchForWorktree,
-                      branch: buildTemporaryWorktreeBranchName(randomHex),
+                      branch: buildTemporaryWorktreeBranchName(
+                        randomHex,
+                        activeProject.worktreeBranchPrefix ?? settings.worktreeBranchPrefix,
+                      ),
                       ...(startFromOrigin ? { startFromOrigin: true } : {}),
                     },
                     runSetupScript: true,
diff --git a/apps/web/src/components/Sidebar.logic.test.ts b/apps/web/src/components/Sidebar.logic.test.ts
index 5339c395d5d9..11bad3afa3b1 100644
--- a/apps/web/src/components/Sidebar.logic.test.ts
+++ b/apps/web/src/components/Sidebar.logic.test.ts
@@ -1058,6 +1058,7 @@ function makeProject(overrides: Partial<Project> = {}): Project {
     updatedAt: "2026-03-09T10:00:00.000Z",
     scripts: [],
     gitHubAccount: null,
+    worktreeBranchPrefix: null,
     ...rest,
   };
 }
diff --git a/apps/web/src/components/SidebarV2.tsx b/apps/web/src/components/SidebarV2.tsx
index 99df66bb50f8..5f9f305b04d4 100644
--- a/apps/web/src/components/SidebarV2.tsx
+++ b/apps/web/src/components/SidebarV2.tsx
@@ -18,6 +18,7 @@ import type {
   ScopedThreadRef,
   SidebarProjectGroupingMode,
 } from "@t3tools/contracts";
+import { sanitizeWorktreeBranchPrefix, WORKTREE_BRANCH_PREFIX } from "@t3tools/shared/git";
 import {
   AlarmClockIcon,
   AlarmClockOffIcon,
@@ -28,6 +29,7 @@ import {
   CircleDashedIcon,
   ClockIcon,
   CopyIcon,
+  FilePenIcon,
   FolderIcon,
   FolderPlusIcon,
   GitBranchIcon,
@@ -95,7 +97,11 @@ import { useCopyToClipboard } from "../hooks/useCopyToClipboard";
 import { useNowMinute } from "../hooks/useNowMinute";
 import { useEnvironments, usePrimaryEnvironmentId } from "../state/environments";
 import { useProjects, useThreadShells } from "../state/entities";
-import { environmentServerConfigsAtom, primaryServerKeybindingsAtom } from "../state/server";
+import {
+  environmentServerConfigsAtom,
+  primaryServerKeybindingsAtom,
+  primaryServerSettingsAtom,
+} from "../state/server";
 import { vcsEnvironment } from "../state/vcs";
 import { threadEnvironment } from "../state/threads";
 import { projectEnvironment } from "../state/projects";
@@ -969,6 +975,17 @@ const SidebarV2Row = memo(function SidebarV2Row(props: {
                 <span className="flex-1" />
               )}
               {prBadge}
+              {gitStatus.data?.hasWorkingTreeChanges ? (
+                <span
+                  className="inline-flex shrink-0 items-center gap-0.5 font-mono text-amber-600 dark:text-amber-400"
+                  title={`${gitStatus.data.workingTree.files.length} modified file${
+                    gitStatus.data.workingTree.files.length === 1 ? "" : "s"
+                  } in the working tree`}
+                >
+                  <FilePenIcon aria-hidden className="size-3" />
+                  {gitStatus.data.workingTree.files.length}
+                </span>
+              ) : null}
               {diff ? (
                 <span className="shrink-0 font-mono">
                   <span className="text-emerald-600 dark:text-emerald-400">+{diff.insertions}</span>{" "}
@@ -1243,6 +1260,7 @@ export default function SidebarV2() {
     [sidebarProjectSortOrder, threads, unsortedProjectGroups],
   );
   const serverProviders = useAtomValue(primaryServerProvidersAtom);
+  const globalWorktreeBranchPrefix = useAtomValue(primaryServerSettingsAtom).worktreeBranchPrefix;
   const providerEntryByInstanceId = useMemo(
     () =>
       new Map(
@@ -1511,6 +1529,29 @@ export default function SidebarV2() {
     [updateProject],
   );
 
+  const updateProjectWorktreeBranchPrefix = useCallback(
+    async (member: SidebarProjectGroupMember, rawValue: string) => {
+      const trimmed = rawValue.trim();
+      const nextPrefix = trimmed.length === 0 ? null : sanitizeWorktreeBranchPrefix(trimmed);
+      if ((member.worktreeBranchPrefix ?? null) === nextPrefix) return;
+      const result = await updateProject({
+        environmentId: member.environmentId,
+        input: { projectId: member.id, worktreeBranchPrefix: nextPrefix },
+      });
+      if (result._tag === "Failure" && !isAtomCommandInterrupted(result)) {
+        const error = squashAtomCommandFailure(result);
+        toastManager.add(
+          stackedThreadToast({
+            type: "error",
+            title: "Failed to update branch prefix",
+            description: error instanceof Error ? error.message : "An error occurred.",
+          }),
+        );
+      }
+    },
+    [updateProject],
+  );
+
   const updateProjectGroupingPreference = useCallback(
     (member: SidebarProjectGroupMember, selection: SidebarProjectGroupingMode | "inherit") => {
       const overrideKey = deriveProjectGroupingOverrideKey(member);
@@ -2858,6 +2899,35 @@ export default function SidebarV2() {
                       member={member}
                       onSelect={updateProjectGitHubAccount}
                     />
+                    <label className="grid min-w-0 gap-1.5">
+                      <span className="font-medium text-foreground">Worktree branch prefix</span>
+                      <Input
+                        key={`prefix:${member.physicalProjectKey}:${member.worktreeBranchPrefix ?? ""}`}
+                        aria-label={`Worktree branch prefix in ${member.environmentLabel ?? "current environment"}`}
+                        defaultValue={member.worktreeBranchPrefix ?? ""}
+                        placeholder={
+                          globalWorktreeBranchPrefix.trim().length > 0
+                            ? globalWorktreeBranchPrefix
+                            : WORKTREE_BRANCH_PREFIX
+                        }
+                        onBlur={(event) => {
+                          void updateProjectWorktreeBranchPrefix(member, event.currentTarget.value);
+                        }}
+                        onKeyDown={(event) => {
+                          if (event.key === "Enter") event.currentTarget.blur();
+                        }}
+                      />
+                      <span className="text-[11px] text-muted-foreground">
+                        New worktree branches use{" "}
+                        <code>
+                          {sanitizeWorktreeBranchPrefix(
+                            member.worktreeBranchPrefix ?? globalWorktreeBranchPrefix,
+                          )}
+                          /…
+                        </code>
+                        {member.worktreeBranchPrefix === null ? " (global default)" : null}
+                      </span>
+                    </label>
                   </div>
                   <ProjectDefaultAgentField
                     idPrefix={`project-agent-${member.physicalProjectKey}`}
diff --git a/apps/web/src/components/settings/SettingsPanels.tsx b/apps/web/src/components/settings/SettingsPanels.tsx
index 2b1d0f88216a..d728691665d3 100644
--- a/apps/web/src/components/settings/SettingsPanels.tsx
+++ b/apps/web/src/components/settings/SettingsPanels.tsx
@@ -44,6 +44,7 @@ import {
   resolveServerBackgroundActivitySettings,
 } from "@t3tools/shared/backgroundActivitySettings";
 import { createModelSelection } from "@t3tools/shared/model";
+import { sanitizeWorktreeBranchPrefix, WORKTREE_BRANCH_PREFIX } from "@t3tools/shared/git";
 import * as Arr from "effect/Array";
 import * as Duration from "effect/Duration";
 import * as Equal from "effect/Equal";
@@ -1582,6 +1583,35 @@ export function GeneralSettingsPanel() {
           }
         />
 
+        <SettingsRow
+          title="Worktree branch prefix"
+          description={`Default prefix for auto-created worktree branches (${sanitizeWorktreeBranchPrefix(
+            settings.worktreeBranchPrefix,
+          )}/…). Leave empty to use "${WORKTREE_BRANCH_PREFIX}". A project can override this in its settings.`}
+          resetAction={
+            settings.worktreeBranchPrefix !== DEFAULT_UNIFIED_SETTINGS.worktreeBranchPrefix ? (
+              <SettingResetButton
+                label="worktree branch prefix"
+                onClick={() =>
+                  updateSettings({
+                    worktreeBranchPrefix: DEFAULT_UNIFIED_SETTINGS.worktreeBranchPrefix,
+                  })
+                }
+              />
+            ) : null
+          }
+          control={
+            <DraftInput
+              className="w-full sm:w-72"
+              value={settings.worktreeBranchPrefix}
+              onCommit={(next) => updateSettings({ worktreeBranchPrefix: next })}
+              placeholder={WORKTREE_BRANCH_PREFIX}
+              spellCheck={false}
+              aria-label="Worktree branch prefix"
+            />
+          }
+        />
+
         <SettingsRow
           title="Archive confirmation"
           description="Require a second click on the inline archive action before a thread is archived."
diff --git a/apps/web/src/environmentGrouping.test.ts b/apps/web/src/environmentGrouping.test.ts
index 36c1b3d8063f..b6c9cc74c7eb 100644
--- a/apps/web/src/environmentGrouping.test.ts
+++ b/apps/web/src/environmentGrouping.test.ts
@@ -47,6 +47,7 @@ function makeProject(overrides: Partial<Project> = {}): Project {
     updatedAt: "2026-01-01T00:00:00.000Z",
     scripts: [],
     gitHubAccount: null,
+    worktreeBranchPrefix: null,
     ...overrides,
   };
 }
diff --git a/packages/client-runtime/src/operations/projects.test.ts b/packages/client-runtime/src/operations/projects.test.ts
index 6f43afd6dd9b..3cfa2bf4a771 100644
--- a/packages/client-runtime/src/operations/projects.test.ts
+++ b/packages/client-runtime/src/operations/projects.test.ts
@@ -103,6 +103,7 @@ describe("add project shared logic", () => {
         repositoryIdentity: null,
         defaultModelSelection: null,
         gitHubAccount: null,
+        worktreeBranchPrefix: null,
         scripts: [],
       },
       {
@@ -115,6 +116,7 @@ describe("add project shared logic", () => {
         repositoryIdentity: null,
         defaultModelSelection: null,
         gitHubAccount: null,
+        worktreeBranchPrefix: null,
         scripts: [],
       },
     ];
diff --git a/packages/client-runtime/src/state/entities.test.ts b/packages/client-runtime/src/state/entities.test.ts
index cc0f37274d60..08c43c5287ff 100644
--- a/packages/client-runtime/src/state/entities.test.ts
+++ b/packages/client-runtime/src/state/entities.test.ts
@@ -116,6 +116,7 @@ const SNAPSHOT: OrchestrationShellSnapshot = {
       repositoryIdentity: null,
       defaultModelSelection: null,
       gitHubAccount: null,
+      worktreeBranchPrefix: null,
       scripts: [],
       createdAt: "2026-06-01T00:00:00.000Z",
       updatedAt: "2026-06-01T00:00:00.000Z",
@@ -127,6 +128,7 @@ const SNAPSHOT: OrchestrationShellSnapshot = {
       repositoryIdentity: null,
       defaultModelSelection: null,
       gitHubAccount: null,
+      worktreeBranchPrefix: null,
       scripts: [],
       createdAt: "2026-06-01T00:00:00.000Z",
       updatedAt: "2026-06-01T00:00:00.000Z",
diff --git a/packages/client-runtime/src/state/shellReducer.test.ts b/packages/client-runtime/src/state/shellReducer.test.ts
index 518b4c26a6a8..aef92ec0f8f9 100644
--- a/packages/client-runtime/src/state/shellReducer.test.ts
+++ b/packages/client-runtime/src/state/shellReducer.test.ts
@@ -19,6 +19,7 @@ const stubProject = {
   repositoryIdentity: null,
   defaultModelSelection: null,
   gitHubAccount: null,
+  worktreeBranchPrefix: null,
   scripts: [],
   createdAt: "2026-04-01T00:00:00.000Z",
   updatedAt: "2026-04-01T00:00:00.000Z",
diff --git a/packages/contracts/src/orchestration.ts b/packages/contracts/src/orchestration.ts
index bd89e1e4e0bd..544a2e20cb2f 100644
--- a/packages/contracts/src/orchestration.ts
+++ b/packages/contracts/src/orchestration.ts
@@ -222,6 +222,13 @@ export const OrchestrationProject = Schema.Struct({
   gitHubAccount: Schema.NullOr(GitHubAccountRef).pipe(
     Schema.withDecodingDefault(Effect.succeed(null)),
   ),
+  /**
+   * Branch-name prefix for auto-created worktree branches (e.g. `feature`
+   * produces `feature/<slug>`). Null falls back to the default prefix.
+   */
+  worktreeBranchPrefix: Schema.NullOr(TrimmedNonEmptyString).pipe(
+    Schema.withDecodingDefault(Effect.succeed(null)),
+  ),
   scripts: Schema.Array(ProjectScript),
   createdAt: IsoDateTime,
   updatedAt: IsoDateTime,
@@ -402,6 +409,9 @@ export const OrchestrationProjectShell = Schema.Struct({
   gitHubAccount: Schema.NullOr(GitHubAccountRef).pipe(
     Schema.withDecodingDefault(Effect.succeed(null)),
   ),
+  worktreeBranchPrefix: Schema.NullOr(TrimmedNonEmptyString).pipe(
+    Schema.withDecodingDefault(Effect.succeed(null)),
+  ),
   scripts: Schema.Array(ProjectScript),
   createdAt: IsoDateTime,
   updatedAt: IsoDateTime,
@@ -532,6 +542,7 @@ export const ProjectCreateCommand = Schema.Struct({
   createWorkspaceRootIfMissing: Schema.optional(Schema.Boolean),
   defaultModelSelection: Schema.optional(Schema.NullOr(ModelSelection)),
   gitHubAccount: Schema.optional(Schema.NullOr(GitHubAccountRef)),
+  worktreeBranchPrefix: Schema.optional(Schema.NullOr(TrimmedNonEmptyString)),
   createdAt: IsoDateTime,
 });
 
@@ -543,6 +554,7 @@ const ProjectMetaUpdateCommand = Schema.Struct({
   workspaceRoot: Schema.optional(TrimmedNonEmptyString),
   defaultModelSelection: Schema.optional(Schema.NullOr(ModelSelection)),
   gitHubAccount: Schema.optional(Schema.NullOr(GitHubAccountRef)),
+  worktreeBranchPrefix: Schema.optional(Schema.NullOr(TrimmedNonEmptyString)),
   scripts: Schema.optional(Schema.Array(ProjectScript)),
 });
 
@@ -930,6 +942,7 @@ export const ProjectCreatedPayload = Schema.Struct({
   repositoryIdentity: Schema.optional(Schema.NullOr(RepositoryIdentity)),
   defaultModelSelection: Schema.NullOr(ModelSelection),
   gitHubAccount: Schema.optional(Schema.NullOr(GitHubAccountRef)),
+  worktreeBranchPrefix: Schema.optional(Schema.NullOr(TrimmedNonEmptyString)),
   scripts: Schema.Array(ProjectScript),
   createdAt: IsoDateTime,
   updatedAt: IsoDateTime,
@@ -942,6 +955,7 @@ export const ProjectMetaUpdatedPayload = Schema.Struct({
   repositoryIdentity: Schema.optional(Schema.NullOr(RepositoryIdentity)),
   defaultModelSelection: Schema.optional(Schema.NullOr(ModelSelection)),
   gitHubAccount: Schema.optional(Schema.NullOr(GitHubAccountRef)),
+  worktreeBranchPrefix: Schema.optional(Schema.NullOr(TrimmedNonEmptyString)),
   scripts: Schema.optional(Schema.Array(ProjectScript)),
   updatedAt: IsoDateTime,
 });
diff --git a/packages/contracts/src/settings.ts b/packages/contracts/src/settings.ts
index 74fa5a8bb849..5e1cba80bf95 100644
--- a/packages/contracts/src/settings.ts
+++ b/packages/contracts/src/settings.ts
@@ -517,6 +517,13 @@ export const ServerSettings = Schema.Struct({
     Schema.withDecodingDefault(Effect.succeed(true)),
   ),
   addProjectBaseDirectory: TrimmedString.pipe(Schema.withDecodingDefault(Effect.succeed(""))),
+  /**
+   * Global default branch-name prefix for auto-created worktree branches
+   * (e.g. `feature` → `feature/<slug>`). Empty falls back to the built-in
+   * default (`t3code`). A project's own `worktreeBranchPrefix`, when set,
+   * overrides this.
+   */
+  worktreeBranchPrefix: TrimmedString.pipe(Schema.withDecodingDefault(Effect.succeed(""))),
   textGenerationModelSelection: ModelSelection.pipe(
     Schema.withDecodingDefault(
       Effect.succeed({
@@ -665,6 +672,7 @@ export const ServerSettingsPatch = Schema.Struct({
   defaultThreadEnvMode: Schema.optionalKey(ThreadEnvMode),
   newWorktreesStartFromOrigin: Schema.optionalKey(Schema.Boolean),
   addProjectBaseDirectory: Schema.optionalKey(TrimmedString),
+  worktreeBranchPrefix: Schema.optionalKey(TrimmedString),
   textGenerationModelSelection: Schema.optionalKey(ModelSelectionPatch),
   sourceControlWritingStyle: Schema.optionalKey(
     Schema.Struct({
diff --git a/packages/shared/src/git.test.ts b/packages/shared/src/git.test.ts
index 96539f0aae24..7fa77ae3c09e 100644
--- a/packages/shared/src/git.test.ts
+++ b/packages/shared/src/git.test.ts
@@ -7,6 +7,7 @@ import {
   isTemporaryWorktreeBranch,
   normalizeGitRemoteUrl,
   parseGitHubRepositoryNameWithOwnerFromRemoteUrl,
+  sanitizeWorktreeBranchPrefix,
   WORKTREE_BRANCH_PREFIX,
 } from "./git.ts";
 
@@ -99,6 +100,34 @@ describe("isTemporaryWorktreeBranch", () => {
     expect(isTemporaryWorktreeBranch("main")).toBe(false);
     expect(isTemporaryWorktreeBranch(`${WORKTREE_BRANCH_PREFIX}/deadbeef-extra`)).toBe(false);
   });
+
+  it("recognizes temporary branches created under a custom prefix", () => {
+    const branch = buildTemporaryWorktreeBranchName(() => "deadbeef", "feature");
+    expect(branch).toBe("feature/deadbeef");
+    expect(isTemporaryWorktreeBranch(branch)).toBe(true);
+    expect(isTemporaryWorktreeBranch("feature/f4ae4e0e-f971-4d48-b4f2-9cf0aa54ab12")).toBe(true);
+  });
+});
+
+describe("sanitizeWorktreeBranchPrefix", () => {
+  it("falls back to the default prefix for empty or nullish input", () => {
+    expect(sanitizeWorktreeBranchPrefix(null)).toBe(WORKTREE_BRANCH_PREFIX);
+    expect(sanitizeWorktreeBranchPrefix(undefined)).toBe(WORKTREE_BRANCH_PREFIX);
+    expect(sanitizeWorktreeBranchPrefix("   ")).toBe(WORKTREE_BRANCH_PREFIX);
+    expect(sanitizeWorktreeBranchPrefix("///")).toBe(WORKTREE_BRANCH_PREFIX);
+  });
+
+  it("normalizes a prefix into a single lowercase ref segment", () => {
+    expect(sanitizeWorktreeBranchPrefix("Feature")).toBe("feature");
+    expect(sanitizeWorktreeBranchPrefix("my feature")).toBe("my-feature");
+    expect(sanitizeWorktreeBranchPrefix("team/wip")).toBe("team-wip");
+  });
+
+  it("keeps the sanitized prefix as a valid single-segment temp branch", () => {
+    const branch = buildTemporaryWorktreeBranchName(() => "deadbeef", "team/wip");
+    expect(branch).toBe("team-wip/deadbeef");
+    expect(isTemporaryWorktreeBranch(branch)).toBe(true);
+  });
 });
 
 describe("applyGitStatusStreamEvent", () => {
diff --git a/packages/shared/src/git.ts b/packages/shared/src/git.ts
index 71fe2e806cfc..dd9181ad1102 100644
--- a/packages/shared/src/git.ts
+++ b/packages/shared/src/git.ts
@@ -11,13 +11,15 @@ import * as Result from "effect/Result";
 import { detectSourceControlProviderFromRemoteUrl } from "./sourceControl.ts";
 
 export const WORKTREE_BRANCH_PREFIX = "t3code";
-// Canonical form is `t3code/<8 hex>`. Older mobile builds generated `t3code/<uuid>`
+// Canonical form is `<prefix>/<8 hex>`, where `<prefix>` is per-project
+// configurable (default `t3code`). Older mobile builds generated `<prefix>/<uuid>`
 // via Crypto.randomUUID() (always RFC 4122 v4), so the matcher also accepts exactly
 // that shape — version nibble `4`, variant nibble `[89ab]` — to keep those threads
 // eligible for branch regeneration without loosening beyond what was ever generated.
-const TEMP_WORKTREE_BRANCH_PATTERN = new RegExp(
-  `^${WORKTREE_BRANCH_PREFIX}\\/(?:[0-9a-f]{8}|[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12})$`,
-);
+// The prefix is intentionally matched as any single ref segment rather than a fixed
+// literal so branches created under a custom prefix are still recognized.
+const TEMP_WORKTREE_BRANCH_PATTERN =
+  /^[^/\s]+\/(?:[0-9a-f]{8}|[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12})$/;
 
 /**
  * Sanitize an arbitrary string into a valid, lowercase git refName fragment.
@@ -92,8 +94,32 @@ export function deriveLocalBranchNameFromRemoteRef(branchName: string): string {
   return branchName.slice(firstSeparatorIndex + 1);
 }
 
+/**
+ * Normalize a user-provided worktree branch prefix into a single, valid,
+ * lowercase git ref segment (no slashes). Falls back to the default prefix
+ * when the input is empty/null or sanitizes to nothing.
+ */
+export function sanitizeWorktreeBranchPrefix(raw: string | null | undefined): string {
+  if (raw === null || raw === undefined) {
+    return WORKTREE_BRANCH_PREFIX;
+  }
+  const normalized = raw
+    .trim()
+    .toLowerCase()
+    .replace(/['"`]/g, "")
+    .replace(/[^a-z0-9/_-]+/g, "-")
+    // A prefix must be a single ref segment so the temp branch stays `prefix/token`.
+    .replace(/[/]+/g, "-")
+    .replace(/-+/g, "-")
+    .replace(/^[._-]+|[._-]+$/g, "")
+    .slice(0, 64)
+    .replace(/[._-]+$/g, "");
+  return normalized.length > 0 ? normalized : WORKTREE_BRANCH_PREFIX;
+}
+
 export function buildTemporaryWorktreeBranchName(
   randomHex: (byteLength: number) => string,
+  prefix?: string | null,
 ): string {
   // Normalize to exactly 8 lowercase hex chars so a UUID-shaped callback
   // still produces the canonical temporary branch form.
@@ -101,7 +127,7 @@ export function buildTemporaryWorktreeBranchName(
     .toLowerCase()
     .replace(/[^0-9a-f]/g, "")
     .slice(0, 8);
-  return `${WORKTREE_BRANCH_PREFIX}/${token}`;
+  return `${sanitizeWorktreeBranchPrefix(prefix)}/${token}`;
 }
 
 export function isTemporaryWorktreeBranch(refName: string): boolean {