fix(server): rename worktree branches from prompt + attachments

Replace top-level `attachments` and `nameContext` on `create_paseo_worktree_request` with `firstAgentContext: { prompt?, attachments? }`, the single signal driving auto-rename. Drop the `worktreeSlug || …` short-circuits so a random placeholder slug no longer blocks renaming, drop the attachment-as-PR fallback in favor of explicit `githubPrNumber`, and reshape the MCP `create_worktree` tool around a `target` discriminated union (`branch-off` / `checkout-branch` / `checkout-pr`) with concise field descriptions so callers stop misreading `prompt` as a name field.

packages/app/src/components/workspace-setup-dialog.tsx

@@ -14,11 +14,7 @@ import { normalizeAgentSnapshot } from "@/utils/agent-snapshots";
 import { encodeImages } from "@/utils/encode-images";
 import { toErrorMessage } from "@/utils/error-messages";
 import { splitComposerAttachmentsForSubmit } from "@/components/composer-attachments";
-import type {
-  CreateAgentRequestOptions,
-  CreatePaseoWorktreeInput,
-  DaemonClient,
-} from "@server/client/daemon-client";
+import type { CreateAgentRequestOptions, DaemonClient } from "@server/client/daemon-client";
 import { projectIconPlaceholderLabelFromDisplayName } from "@/utils/project-display-name";
 import { requireWorkspaceExecutionAuthority } from "@/utils/workspace-execution";
 import { navigateToPreparedWorkspaceTab } from "@/utils/workspace-navigation";
@@ -73,24 +69,19 @@ function buildChatDraftComposerArgs({
   };
 }
 
-type WorkspaceCreationAttachments = NonNullable<CreatePaseoWorktreeInput["attachments"]>;
-
 async function callWorkspaceCreation({
   creationMethod,
   connectedClient,
   input,
-  wirePayload,
 }: {
   creationMethod: "create_worktree" | "open_project";
   connectedClient: DaemonClient;
   input: { cwd: string };
-  wirePayload: { attachments: WorkspaceCreationAttachments };
 }) {
   if (creationMethod === "create_worktree") {
     return connectedClient.createPaseoWorktree({
       cwd: input.cwd,
       worktreeSlug: createNameId(),
-      ...(wirePayload.attachments.length > 0 ? { attachments: wirePayload.attachments } : {}),
     });
   }
   return connectedClient.openProject(input.cwd);
@@ -228,12 +219,10 @@ export function WorkspaceSetupDialog() {
       }
 
       const connectedClient = withConnectedClient();
-      const wirePayload = splitComposerAttachmentsForSubmit(input.attachments);
       const payload = await callWorkspaceCreation({
         creationMethod: pendingWorkspaceSetup.creationMethod,
         connectedClient,
         input,
-        wirePayload,
       });
 
       if (payload.error || !payload.workspace) {

packages/app/src/screens/new-workspace-screen.test.tsx

@@ -699,6 +699,7 @@ describe("NewWorkspaceScreen picker payload", () => {
     await flush();
 
     expect(mockClient.createPaseoWorktree).toHaveBeenCalledTimes(1);
+    expect(firstCreateWorktreeCall().firstAgentContext?.prompt).toBe("please review this change");
     expect(mockClient.createAgent).not.toHaveBeenCalled();
     expect(saveDraftInputMock).toHaveBeenCalledWith({
       draftKey: "draft:server:draft-new-workspace",
@@ -876,7 +877,7 @@ describe("NewWorkspaceScreen picker payload", () => {
     await flush();
 
     const call = firstCreateWorktreeCall();
-    const attachments = call.attachments ?? [];
+    const attachments = call.firstAgentContext?.attachments ?? [];
     expect(attachments).toHaveLength(1);
     expect(attachments[0]).toMatchObject({ type: "github_pr", number: 202 });
   });
@@ -907,8 +908,11 @@ describe("NewWorkspaceScreen picker payload", () => {
     await flush();
 
     const call = firstCreateWorktreeCall();
-    expect(call.attachments).toHaveLength(1);
-    expect(call.attachments?.[0]).toMatchObject({ type: "github_pr", number: 202 });
+    expect(call.firstAgentContext?.attachments).toHaveLength(1);
+    expect(call.firstAgentContext?.attachments?.[0]).toMatchObject({
+      type: "github_pr",
+      number: 202,
+    });
   });
 
   it("omits PR rows from the picker when GitHub features are disabled", async () => {

packages/app/src/screens/new-workspace-screen.tsx

@@ -293,6 +293,7 @@ interface CreateChatAgentInput {
   composerState: ReturnType<typeof useAgentInputDraft>["composerState"];
   ensureWorkspace: (input: {
     cwd: string;
+    prompt: string;
     attachments: AgentAttachment[];
   }) => Promise<ReturnType<typeof normalizeWorkspaceDescriptor>>;
   serverId: string;
@@ -310,7 +311,11 @@ async function runCreateChatAgent(input: CreateChatAgentInput): Promise<void> {
     throw new Error("Select a model");
   }
   const { attachments: reviewAttachments } = splitComposerAttachmentsForSubmit(attachments);
-  const ensuredWorkspace = await ensureWorkspace({ cwd, attachments: reviewAttachments });
+  const ensuredWorkspace = await ensureWorkspace({
+    cwd,
+    prompt: text,
+    attachments: reviewAttachments,
+  });
   submitWorkspaceDraft({
     serverId,
     draftKey,
@@ -588,13 +593,22 @@ export function NewWorkspaceScreen({
   }, []);
 
   const buildCreateWorktreeInput = useCallback(
-    (input: { cwd: string; attachments: AgentAttachment[] }) => {
+    (input: { cwd: string; prompt: string; attachments: AgentAttachment[] }) => {
       const checkoutRequest = pickerItemToCheckoutRequest(selectedItem);
+      const trimmedPrompt = input.prompt.trim();
+      const hasFirstAgentContext = trimmedPrompt.length > 0 || input.attachments.length > 0;
 
       return {
         cwd: input.cwd,
         worktreeSlug: createNameId(),
-        ...(input.attachments.length > 0 ? { attachments: input.attachments } : {}),
+        ...(hasFirstAgentContext
+          ? {
+              firstAgentContext: {
+                ...(trimmedPrompt ? { prompt: trimmedPrompt } : {}),
+                ...(input.attachments.length > 0 ? { attachments: input.attachments } : {}),
+              },
+            }
+          : {}),
         ...checkoutRequest,
       };
     },
@@ -602,7 +616,7 @@ export function NewWorkspaceScreen({
   );
 
   const ensureWorkspace = useCallback(
-    async (input: { cwd: string; attachments: AgentAttachment[] }) => {
+    async (input: { cwd: string; prompt: string; attachments: AgentAttachment[] }) => {
       if (createdWorkspace) {
         return createdWorkspace;
       }