From 85147a4fbd8e0f9224519ea483c8000f1dfc71ea Mon Sep 17 00:00:00 2001
From: Alex Southwell <4596216+saphid@users.noreply.github.com>
Date: Tue, 3 Nov 2026 12:15:59 +1100
Subject: [PATCH] fix(server): worktree handoff follows the project's
 start-from-origin setting

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .../server/src/mcp/WorktreeMcpService.test.ts | 22 ++++++++++++++++++-
 apps/server/src/mcp/WorktreeMcpService.ts     | 18 ++++++++++-----
 2 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/apps/server/src/mcp/WorktreeMcpService.test.ts b/apps/server/src/mcp/WorktreeMcpService.test.ts
index 51c86f3e3a165..eb8b4b5b1e31c 100644
--- a/apps/server/src/mcp/WorktreeMcpService.test.ts
+++ b/apps/server/src/mcp/WorktreeMcpService.test.ts
@@ -96,6 +96,7 @@ interface HarnessOptions {
   readonly currentBranch?: string | null;
   readonly notARepo?: boolean;
   readonly newWorktreesStartFromOrigin?: boolean;
+  readonly projectNewWorktreesStartFromOrigin?: boolean;
   readonly setupScript?: "started" | "no-script" | "fails" | "dies";
   readonly dispatchFails?: boolean;
   readonly dispatchDies?: boolean;
@@ -302,6 +303,15 @@ const makeHarness = (options: HarnessOptions = {}) => {
         } satisfies Partial<ProjectService.ProjectService["Service"]>),
         ServerSettings.layerTest({
           newWorktreesStartFromOrigin: options.newWorktreesStartFromOrigin ?? false,
+          ...(options.projectNewWorktreesStartFromOrigin === undefined
+            ? {}
+            : {
+                projectSettingsOverrides: {
+                  [projectId]: {
+                    newWorktreesStartFromOrigin: options.projectNewWorktreesStartFromOrigin,
+                  },
+                },
+              }),
         }),
         Layer.mock(GitWorkflowService.GitWorkflowService)({
           listRefs,
@@ -522,6 +532,15 @@ describe("t3_worktree_handoff", () => {
     });
   });
 
+  it.effect("defaults startFromOrigin to the project's override", () => {
+    const harness = makeHarness({ projectNewWorktreesStartFromOrigin: true });
+    return Effect.gen(function* () {
+      const result = yield* runHandoff(harness, { branch: "feature/project-origin" });
+      expect(harness.fetchWorktreeBaseCommit).toHaveBeenCalled();
+      expect(result.startedFromOrigin).toBe(true);
+    });
+  });
+
   it.effect("removes the created worktree when the thread update dies with a defect", () => {
     const harness = makeHarness({ dispatchDies: true });
     return Effect.gen(function* () {
@@ -679,6 +698,7 @@ describe("t3_worktree_status", () => {
         worktreePath: "/worktrees/project/existing",
         branch: "feature/existing",
       },
+      projectNewWorktreesStartFromOrigin: true,
     });
     return Effect.gen(function* () {
       const result = yield* runStatus(harness);
@@ -686,7 +706,7 @@ describe("t3_worktree_status", () => {
         attached: true,
         worktreePath: "/worktrees/project/existing",
         branch: "feature/existing",
-        defaultStartFromOrigin: false,
+        defaultStartFromOrigin: true,
       });
     });
   });
diff --git a/apps/server/src/mcp/WorktreeMcpService.ts b/apps/server/src/mcp/WorktreeMcpService.ts
index 8a2231f6e4df4..bffae891d5f23 100644
--- a/apps/server/src/mcp/WorktreeMcpService.ts
+++ b/apps/server/src/mcp/WorktreeMcpService.ts
@@ -9,6 +9,7 @@ import {
   type WorktreeMcpSetupScriptStatus,
   type WorktreeMcpStatusResult,
 } from "@t3tools/contracts";
+import { resolveProjectSettings } from "@t3tools/shared/projectSettings";
 import * as Cause from "effect/Cause";
 import * as Context from "effect/Context";
 import * as SecureRandom from "effect/crypto/SecureRandom";
@@ -116,10 +117,14 @@ const make = Effect.gen(function* () {
       ),
     );
 
-  const readDefaultStartFromOrigin = serverSettings.getSettings.pipe(
-    Effect.map((settings) => settings.newWorktreesStartFromOrigin),
-    asOperationFailed("Unable to read server settings"),
-  );
+  const readDefaultStartFromOrigin = (projectId: ProjectId) =>
+    serverSettings.getSettings.pipe(
+      Effect.map(
+        (settings) =>
+          resolveProjectSettings(settings, projectId).settings.newWorktreesStartFromOrigin,
+      ),
+      asOperationFailed("Unable to read server settings"),
+    );
 
   const handoffIds = (scope: McpThreadInvocationScope) =>
     random.uuidV4().pipe(
@@ -205,7 +210,8 @@ const make = Effect.gen(function* () {
       baseRef = localStatus.refName;
     }
 
-    const startFromOrigin = input.startFromOrigin ?? (yield* readDefaultStartFromOrigin);
+    const startFromOrigin =
+      input.startFromOrigin ?? (yield* readDefaultStartFromOrigin(project.id));
 
     let worktreeBaseRef = baseRef;
     let baseRefName = baseRef;
@@ -415,7 +421,7 @@ const make = Effect.gen(function* () {
       const projection = yield* loadThread(scope);
       const project = yield* loadProject(scope, projection.thread.projectId);
 
-      const defaultStartFromOrigin = yield* readDefaultStartFromOrigin;
+      const defaultStartFromOrigin = yield* readDefaultStartFromOrigin(project.id);
 
       const result: WorktreeMcpStatusResult = {
         attached: projection.thread.worktreePath !== null,