Rename Foundry handoffs to tasks (#239)

* Restore foundry onboarding stack

* Consolidate foundry rename

* Create foundry tasks without prompts

* Rename Foundry handoffs to tasks

foundry/packages/client/src/mock/backend-client.ts

@@ -0,0 +1,540 @@
+import type {
+  AddRepoInput,
+  CreateTaskInput,
+  FoundryAppSnapshot,
+  TaskRecord,
+  TaskSummary,
+  TaskWorkbenchChangeModelInput,
+  TaskWorkbenchCreateTaskInput,
+  TaskWorkbenchCreateTaskResponse,
+  TaskWorkbenchDiffInput,
+  TaskWorkbenchRenameInput,
+  TaskWorkbenchRenameSessionInput,
+  TaskWorkbenchSelectInput,
+  TaskWorkbenchSetSessionUnreadInput,
+  TaskWorkbenchSendMessageInput,
+  TaskWorkbenchSnapshot,
+  TaskWorkbenchTabInput,
+  TaskWorkbenchUpdateDraftInput,
+  HistoryEvent,
+  HistoryQueryInput,
+  ProviderId,
+  RepoOverview,
+  RepoRecord,
+  RepoStackActionInput,
+  RepoStackActionResult,
+  StarSandboxAgentRepoResult,
+  SwitchResult,
+} from "@sandbox-agent/foundry-shared";
+import type { ProcessCreateRequest, ProcessLogFollowQuery, ProcessLogsResponse, ProcessSignalQuery } from "sandbox-agent";
+import type { BackendClient, SandboxProcessRecord, SandboxSessionEventRecord, SandboxSessionRecord } from "../backend-client.js";
+import { getSharedMockWorkbenchClient } from "./workbench-client.js";
+
+interface MockProcessRecord extends SandboxProcessRecord {
+  logText: string;
+}
+
+function notSupported(name: string): never {
+  throw new Error(`${name} is not supported by the mock backend client.`);
+}
+
+function encodeBase64Utf8(value: string): string {
+  if (typeof Buffer !== "undefined") {
+    return Buffer.from(value, "utf8").toString("base64");
+  }
+  return globalThis.btoa(unescape(encodeURIComponent(value)));
+}
+
+function nowMs(): number {
+  return Date.now();
+}
+
+function mockRepoRemote(label: string): string {
+  return `https://example.test/${label}.git`;
+}
+
+function mockCwd(repoLabel: string, taskId: string): string {
+  return `/mock/${repoLabel.replace(/\//g, "-")}/${taskId}`;
+}
+
+function unsupportedAppSnapshot(): FoundryAppSnapshot {
+  return {
+    auth: { status: "signed_out", currentUserId: null },
+    activeOrganizationId: null,
+    onboarding: {
+      starterRepo: {
+        repoFullName: "rivet-dev/sandbox-agent",
+        repoUrl: "https://github.com/rivet-dev/sandbox-agent",
+        status: "pending",
+        starredAt: null,
+        skippedAt: null,
+      },
+    },
+    users: [],
+    organizations: [],
+  };
+}
+
+function toTaskStatus(status: TaskRecord["status"], archived: boolean): TaskRecord["status"] {
+  if (archived) {
+    return "archived";
+  }
+  return status;
+}
+
+export function createMockBackendClient(defaultWorkspaceId = "default"): BackendClient {
+  const workbench = getSharedMockWorkbenchClient();
+  const listenersBySandboxId = new Map<string, Set<() => void>>();
+  const processesBySandboxId = new Map<string, MockProcessRecord[]>();
+  let nextPid = 4000;
+  let nextProcessId = 1;
+
+  const requireTask = (taskId: string) => {
+    const task = workbench.getSnapshot().tasks.find((candidate) => candidate.id === taskId);
+    if (!task) {
+      throw new Error(`Unknown mock task ${taskId}`);
+    }
+    return task;
+  };
+
+  const ensureProcessList = (sandboxId: string): MockProcessRecord[] => {
+    const existing = processesBySandboxId.get(sandboxId);
+    if (existing) {
+      return existing;
+    }
+    const created: MockProcessRecord[] = [];
+    processesBySandboxId.set(sandboxId, created);
+    return created;
+  };
+
+  const notifySandbox = (sandboxId: string): void => {
+    const listeners = listenersBySandboxId.get(sandboxId);
+    if (!listeners) {
+      return;
+    }
+    for (const listener of [...listeners]) {
+      listener();
+    }
+  };
+
+  const buildTaskRecord = (taskId: string): TaskRecord => {
+    const task = requireTask(taskId);
+    const cwd = mockCwd(task.repoName, task.id);
+    const archived = task.status === "archived";
+    return {
+      workspaceId: defaultWorkspaceId,
+      repoId: task.repoId,
+      repoRemote: mockRepoRemote(task.repoName),
+      taskId: task.id,
+      branchName: task.branch,
+      title: task.title,
+      task: task.title,
+      providerId: "local",
+      status: toTaskStatus(archived ? "archived" : "running", archived),
+      statusMessage: archived ? "archived" : "mock sandbox ready",
+      activeSandboxId: task.id,
+      activeSessionId: task.tabs[0]?.sessionId ?? null,
+      sandboxes: [
+        {
+          sandboxId: task.id,
+          providerId: "local",
+          sandboxActorId: "mock-sandbox",
+          switchTarget: `mock://${task.id}`,
+          cwd,
+          createdAt: task.updatedAtMs,
+          updatedAt: task.updatedAtMs,
+        },
+      ],
+      agentType: task.tabs[0]?.agent === "Codex" ? "codex" : "claude",
+      prSubmitted: Boolean(task.pullRequest),
+      diffStat: task.fileChanges.length > 0 ? `+${task.fileChanges.length}/-${task.fileChanges.length}` : "+0/-0",
+      prUrl: task.pullRequest ? `https://example.test/pr/${task.pullRequest.number}` : null,
+      prAuthor: task.pullRequest ? "mock" : null,
+      ciStatus: null,
+      reviewStatus: null,
+      reviewer: null,
+      conflictsWithMain: "0",
+      hasUnpushed: task.fileChanges.length > 0 ? "1" : "0",
+      parentBranch: null,
+      createdAt: task.updatedAtMs,
+      updatedAt: task.updatedAtMs,
+    };
+  };
+
+  const cloneProcess = (process: MockProcessRecord): MockProcessRecord => ({ ...process });
+
+  const createProcessRecord = (sandboxId: string, cwd: string, request: ProcessCreateRequest): MockProcessRecord => {
+    const processId = `proc_${nextProcessId++}`;
+    const createdAtMs = nowMs();
+    const args = request.args ?? [];
+    const interactive = request.interactive ?? false;
+    const tty = request.tty ?? false;
+    const statusLine = interactive && tty ? "Mock terminal session created.\nInteractive transport is unavailable in mock mode.\n" : "Mock process created.\n";
+    const commandLine = `$ ${[request.command, ...args].join(" ").trim()}\n`;
+    return {
+      id: processId,
+      command: request.command,
+      args,
+      createdAtMs,
+      cwd: request.cwd ?? cwd,
+      exitCode: null,
+      exitedAtMs: null,
+      interactive,
+      pid: nextPid++,
+      status: "running",
+      tty,
+      logText: `${statusLine}${commandLine}`,
+    };
+  };
+
+  return {
+    async getAppSnapshot(): Promise<FoundryAppSnapshot> {
+      return unsupportedAppSnapshot();
+    },
+
+    async signInWithGithub(): Promise<void> {
+      notSupported("signInWithGithub");
+    },
+
+    async signOutApp(): Promise<FoundryAppSnapshot> {
+      return unsupportedAppSnapshot();
+    },
+
+    async skipAppStarterRepo(): Promise<FoundryAppSnapshot> {
+      return unsupportedAppSnapshot();
+    },
+
+    async starAppStarterRepo(): Promise<FoundryAppSnapshot> {
+      return unsupportedAppSnapshot();
+    },
+
+    async selectAppOrganization(): Promise<FoundryAppSnapshot> {
+      return unsupportedAppSnapshot();
+    },
+
+    async updateAppOrganizationProfile(): Promise<FoundryAppSnapshot> {
+      return unsupportedAppSnapshot();
+    },
+
+    async triggerAppRepoImport(): Promise<FoundryAppSnapshot> {
+      return unsupportedAppSnapshot();
+    },
+
+    async reconnectAppGithub(): Promise<void> {
+      notSupported("reconnectAppGithub");
+    },
+
+    async completeAppHostedCheckout(): Promise<void> {
+      notSupported("completeAppHostedCheckout");
+    },
+
+    async openAppBillingPortal(): Promise<void> {
+      notSupported("openAppBillingPortal");
+    },
+
+    async cancelAppScheduledRenewal(): Promise<FoundryAppSnapshot> {
+      return unsupportedAppSnapshot();
+    },
+
+    async resumeAppSubscription(): Promise<FoundryAppSnapshot> {
+      return unsupportedAppSnapshot();
+    },
+
+    async recordAppSeatUsage(): Promise<FoundryAppSnapshot> {
+      return unsupportedAppSnapshot();
+    },
+
+    async addRepo(_workspaceId: string, _remoteUrl: string): Promise<RepoRecord> {
+      notSupported("addRepo");
+    },
+
+    async listRepos(_workspaceId: string): Promise<RepoRecord[]> {
+      return workbench.getSnapshot().repos.map((repo) => ({
+        workspaceId: defaultWorkspaceId,
+        repoId: repo.id,
+        remoteUrl: mockRepoRemote(repo.label),
+        createdAt: nowMs(),
+        updatedAt: nowMs(),
+      }));
+    },
+
+    async createTask(_input: CreateTaskInput): Promise<TaskRecord> {
+      notSupported("createTask");
+    },
+
+    async listTasks(_workspaceId: string, repoId?: string): Promise<TaskSummary[]> {
+      return workbench
+        .getSnapshot()
+        .tasks.filter((task) => !repoId || task.repoId === repoId)
+        .map((task) => ({
+          workspaceId: defaultWorkspaceId,
+          repoId: task.repoId,
+          taskId: task.id,
+          branchName: task.branch,
+          title: task.title,
+          status: task.status === "archived" ? "archived" : "running",
+          updatedAt: task.updatedAtMs,
+        }));
+    },
+
+    async getRepoOverview(_workspaceId: string, _repoId: string): Promise<RepoOverview> {
+      notSupported("getRepoOverview");
+    },
+
+    async runRepoStackAction(_input: RepoStackActionInput): Promise<RepoStackActionResult> {
+      notSupported("runRepoStackAction");
+    },
+
+    async getTask(_workspaceId: string, taskId: string): Promise<TaskRecord> {
+      return buildTaskRecord(taskId);
+    },
+
+    async listHistory(_input: HistoryQueryInput): Promise<HistoryEvent[]> {
+      return [];
+    },
+
+    async switchTask(_workspaceId: string, taskId: string): Promise<SwitchResult> {
+      return {
+        workspaceId: defaultWorkspaceId,
+        taskId,
+        providerId: "local",
+        switchTarget: `mock://${taskId}`,
+      };
+    },
+
+    async attachTask(_workspaceId: string, taskId: string): Promise<{ target: string; sessionId: string | null }> {
+      return {
+        target: `mock://${taskId}`,
+        sessionId: requireTask(taskId).tabs[0]?.sessionId ?? null,
+      };
+    },
+
+    async runAction(_workspaceId: string, _taskId: string): Promise<void> {
+      notSupported("runAction");
+    },
+
+    async createSandboxSession(): Promise<{ id: string; status: "running" | "idle" | "error" }> {
+      notSupported("createSandboxSession");
+    },
+
+    async listSandboxSessions(): Promise<{ items: SandboxSessionRecord[]; nextCursor?: string }> {
+      return { items: [] };
+    },
+
+    async listSandboxSessionEvents(): Promise<{ items: SandboxSessionEventRecord[]; nextCursor?: string }> {
+      return { items: [] };
+    },
+
+    async createSandboxProcess(input: {
+      workspaceId: string;
+      providerId: ProviderId;
+      sandboxId: string;
+      request: ProcessCreateRequest;
+    }): Promise<SandboxProcessRecord> {
+      const task = requireTask(input.sandboxId);
+      const processes = ensureProcessList(input.sandboxId);
+      const created = createProcessRecord(input.sandboxId, mockCwd(task.repoName, task.id), input.request);
+      processes.unshift(created);
+      notifySandbox(input.sandboxId);
+      return cloneProcess(created);
+    },
+
+    async listSandboxProcesses(_workspaceId: string, _providerId: ProviderId, sandboxId: string): Promise<{ processes: SandboxProcessRecord[] }> {
+      return {
+        processes: ensureProcessList(sandboxId).map((process) => cloneProcess(process)),
+      };
+    },
+
+    async getSandboxProcessLogs(
+      _workspaceId: string,
+      _providerId: ProviderId,
+      sandboxId: string,
+      processId: string,
+      query?: ProcessLogFollowQuery,
+    ): Promise<ProcessLogsResponse> {
+      const process = ensureProcessList(sandboxId).find((candidate) => candidate.id === processId);
+      if (!process) {
+        throw new Error(`Unknown mock process ${processId}`);
+      }
+      return {
+        processId,
+        stream: query?.stream ?? (process.tty ? "pty" : "combined"),
+        entries: process.logText
+          ? [
+              {
+                data: encodeBase64Utf8(process.logText),
+                encoding: "base64",
+                sequence: 1,
+                stream: query?.stream ?? (process.tty ? "pty" : "combined"),
+                timestampMs: process.createdAtMs,
+              },
+            ]
+          : [],
+      };
+    },
+
+    async stopSandboxProcess(
+      _workspaceId: string,
+      _providerId: ProviderId,
+      sandboxId: string,
+      processId: string,
+      _query?: ProcessSignalQuery,
+    ): Promise<SandboxProcessRecord> {
+      const process = ensureProcessList(sandboxId).find((candidate) => candidate.id === processId);
+      if (!process) {
+        throw new Error(`Unknown mock process ${processId}`);
+      }
+      process.status = "exited";
+      process.exitCode = 0;
+      process.exitedAtMs = nowMs();
+      process.logText += "\n[stopped]\n";
+      notifySandbox(sandboxId);
+      return cloneProcess(process);
+    },
+
+    async killSandboxProcess(
+      _workspaceId: string,
+      _providerId: ProviderId,
+      sandboxId: string,
+      processId: string,
+      _query?: ProcessSignalQuery,
+    ): Promise<SandboxProcessRecord> {
+      const process = ensureProcessList(sandboxId).find((candidate) => candidate.id === processId);
+      if (!process) {
+        throw new Error(`Unknown mock process ${processId}`);
+      }
+      process.status = "exited";
+      process.exitCode = 137;
+      process.exitedAtMs = nowMs();
+      process.logText += "\n[killed]\n";
+      notifySandbox(sandboxId);
+      return cloneProcess(process);
+    },
+
+    async deleteSandboxProcess(_workspaceId: string, _providerId: ProviderId, sandboxId: string, processId: string): Promise<void> {
+      processesBySandboxId.set(
+        sandboxId,
+        ensureProcessList(sandboxId).filter((candidate) => candidate.id !== processId),
+      );
+      notifySandbox(sandboxId);
+    },
+
+    subscribeSandboxProcesses(_workspaceId: string, _providerId: ProviderId, sandboxId: string, listener: () => void): () => void {
+      let listeners = listenersBySandboxId.get(sandboxId);
+      if (!listeners) {
+        listeners = new Set();
+        listenersBySandboxId.set(sandboxId, listeners);
+      }
+      listeners.add(listener);
+      return () => {
+        const current = listenersBySandboxId.get(sandboxId);
+        if (!current) {
+          return;
+        }
+        current.delete(listener);
+        if (current.size === 0) {
+          listenersBySandboxId.delete(sandboxId);
+        }
+      };
+    },
+
+    async sendSandboxPrompt(): Promise<void> {
+      notSupported("sendSandboxPrompt");
+    },
+
+    async sandboxSessionStatus(sessionId: string): Promise<{ id: string; status: "running" | "idle" | "error" }> {
+      return { id: sessionId, status: "idle" };
+    },
+
+    async sandboxProviderState(
+      _workspaceId: string,
+      _providerId: ProviderId,
+      sandboxId: string,
+    ): Promise<{ providerId: ProviderId; sandboxId: string; state: string; at: number }> {
+      return { providerId: "local", sandboxId, state: "running", at: nowMs() };
+    },
+
+    async getSandboxAgentConnection(): Promise<{ endpoint: string; token?: string }> {
+      return { endpoint: "mock://terminal-unavailable" };
+    },
+
+    async getWorkbench(): Promise<TaskWorkbenchSnapshot> {
+      return workbench.getSnapshot();
+    },
+
+    subscribeWorkbench(_workspaceId: string, listener: () => void): () => void {
+      return workbench.subscribe(listener);
+    },
+
+    async createWorkbenchTask(_workspaceId: string, input: TaskWorkbenchCreateTaskInput): Promise<TaskWorkbenchCreateTaskResponse> {
+      return await workbench.createTask(input);
+    },
+
+    async markWorkbenchUnread(_workspaceId: string, input: TaskWorkbenchSelectInput): Promise<void> {
+      await workbench.markTaskUnread(input);
+    },
+
+    async renameWorkbenchTask(_workspaceId: string, input: TaskWorkbenchRenameInput): Promise<void> {
+      await workbench.renameTask(input);
+    },
+
+    async renameWorkbenchBranch(_workspaceId: string, input: TaskWorkbenchRenameInput): Promise<void> {
+      await workbench.renameBranch(input);
+    },
+
+    async createWorkbenchSession(_workspaceId: string, input: TaskWorkbenchSelectInput & { model?: string }): Promise<{ tabId: string }> {
+      return await workbench.addTab(input);
+    },
+
+    async renameWorkbenchSession(_workspaceId: string, input: TaskWorkbenchRenameSessionInput): Promise<void> {
+      await workbench.renameSession(input);
+    },
+
+    async setWorkbenchSessionUnread(_workspaceId: string, input: TaskWorkbenchSetSessionUnreadInput): Promise<void> {
+      await workbench.setSessionUnread(input);
+    },
+
+    async updateWorkbenchDraft(_workspaceId: string, input: TaskWorkbenchUpdateDraftInput): Promise<void> {
+      await workbench.updateDraft(input);
+    },
+
+    async changeWorkbenchModel(_workspaceId: string, input: TaskWorkbenchChangeModelInput): Promise<void> {
+      await workbench.changeModel(input);
+    },
+
+    async sendWorkbenchMessage(_workspaceId: string, input: TaskWorkbenchSendMessageInput): Promise<void> {
+      await workbench.sendMessage(input);
+    },
+
+    async stopWorkbenchSession(_workspaceId: string, input: TaskWorkbenchTabInput): Promise<void> {
+      await workbench.stopAgent(input);
+    },
+
+    async closeWorkbenchSession(_workspaceId: string, input: TaskWorkbenchTabInput): Promise<void> {
+      await workbench.closeTab(input);
+    },
+
+    async publishWorkbenchPr(_workspaceId: string, input: TaskWorkbenchSelectInput): Promise<void> {
+      await workbench.publishPr(input);
+    },
+
+    async revertWorkbenchFile(_workspaceId: string, input: TaskWorkbenchDiffInput): Promise<void> {
+      await workbench.revertFile(input);
+    },
+
+    async health(): Promise<{ ok: true }> {
+      return { ok: true };
+    },
+
+    async useWorkspace(workspaceId: string): Promise<{ workspaceId: string }> {
+      return { workspaceId };
+    },
+
+    async starSandboxAgentRepo(): Promise<StarSandboxAgentRepoResult> {
+      return {
+        repo: "rivet-dev/sandbox-agent",
+        starredAt: nowMs(),
+      };
+    },
+  };
+}

foundry/packages/client/src/mock/latency.ts

@@ -0,0 +1,12 @@
+const MOCK_LATENCY_MIN_MS = 1;
+const MOCK_LATENCY_MAX_MS = 200;
+
+export function randomMockLatencyMs(): number {
+  return Math.floor(Math.random() * (MOCK_LATENCY_MAX_MS - MOCK_LATENCY_MIN_MS + 1)) + MOCK_LATENCY_MIN_MS;
+}
+
+export function injectMockLatency(): Promise<void> {
+  return new Promise((resolve) => {
+    setTimeout(resolve, randomMockLatencyMs());
+  });
+}

foundry/packages/client/src/mock/workbench-client.ts

@@ -0,0 +1,443 @@
+import {
+  MODEL_GROUPS,
+  buildInitialMockLayoutViewModel,
+  groupWorkbenchProjects,
+  nowMs,
+  providerAgent,
+  randomReply,
+  removeFileTreePath,
+  slugify,
+  uid,
+} from "../workbench-model.js";
+import type {
+  TaskWorkbenchAddTabResponse,
+  TaskWorkbenchChangeModelInput,
+  TaskWorkbenchCreateTaskInput,
+  TaskWorkbenchCreateTaskResponse,
+  TaskWorkbenchDiffInput,
+  TaskWorkbenchRenameInput,
+  TaskWorkbenchRenameSessionInput,
+  TaskWorkbenchSelectInput,
+  TaskWorkbenchSetSessionUnreadInput,
+  TaskWorkbenchSendMessageInput,
+  TaskWorkbenchSnapshot,
+  TaskWorkbenchTabInput,
+  TaskWorkbenchUpdateDraftInput,
+  WorkbenchAgentTab as AgentTab,
+  WorkbenchTask as Task,
+  WorkbenchTranscriptEvent as TranscriptEvent,
+} from "@sandbox-agent/foundry-shared";
+import type { TaskWorkbenchClient } from "../workbench-client.js";
+
+function buildTranscriptEvent(params: {
+  sessionId: string;
+  sender: "client" | "agent";
+  createdAt: number;
+  payload: unknown;
+  eventIndex: number;
+}): TranscriptEvent {
+  return {
+    id: uid(),
+    sessionId: params.sessionId,
+    sender: params.sender,
+    createdAt: params.createdAt,
+    payload: params.payload,
+    connectionId: "mock-connection",
+    eventIndex: params.eventIndex,
+  };
+}
+
+class MockWorkbenchStore implements TaskWorkbenchClient {
+  private snapshot = buildInitialMockLayoutViewModel();
+  private listeners = new Set<() => void>();
+  private pendingTimers = new Map<string, ReturnType<typeof setTimeout>>();
+
+  getSnapshot(): TaskWorkbenchSnapshot {
+    return this.snapshot;
+  }
+
+  subscribe(listener: () => void): () => void {
+    this.listeners.add(listener);
+    return () => {
+      this.listeners.delete(listener);
+    };
+  }
+
+  async createTask(input: TaskWorkbenchCreateTaskInput): Promise<TaskWorkbenchCreateTaskResponse> {
+    const id = uid();
+    const tabId = `session-${id}`;
+    const repo = this.snapshot.repos.find((candidate) => candidate.id === input.repoId);
+    if (!repo) {
+      throw new Error(`Cannot create mock task for unknown repo ${input.repoId}`);
+    }
+    const nextTask: Task = {
+      id,
+      repoId: repo.id,
+      title: input.title?.trim() || "New Task",
+      status: "new",
+      repoName: repo.label,
+      updatedAtMs: nowMs(),
+      branch: input.branch?.trim() || null,
+      pullRequest: null,
+      tabs: [
+        {
+          id: tabId,
+          sessionId: tabId,
+          sessionName: "Session 1",
+          agent: providerAgent(
+            MODEL_GROUPS.find((group) => group.models.some((model) => model.id === (input.model ?? "claude-sonnet-4")))?.provider ?? "Claude",
+          ),
+          model: input.model ?? "claude-sonnet-4",
+          status: "idle",
+          thinkingSinceMs: null,
+          unread: false,
+          created: false,
+          draft: { text: "", attachments: [], updatedAtMs: null },
+          transcript: [],
+        },
+      ],
+      fileChanges: [],
+      diffs: {},
+      fileTree: [],
+    };
+
+    this.updateState((current) => ({
+      ...current,
+      tasks: [nextTask, ...current.tasks],
+    }));
+    return { taskId: id, tabId };
+  }
+
+  async markTaskUnread(input: TaskWorkbenchSelectInput): Promise<void> {
+    this.updateTask(input.taskId, (task) => {
+      const targetTab = task.tabs[task.tabs.length - 1] ?? null;
+      if (!targetTab) {
+        return task;
+      }
+
+      return {
+        ...task,
+        tabs: task.tabs.map((tab) => (tab.id === targetTab.id ? { ...tab, unread: true } : tab)),
+      };
+    });
+  }
+
+  async renameTask(input: TaskWorkbenchRenameInput): Promise<void> {
+    const value = input.value.trim();
+    if (!value) {
+      throw new Error(`Cannot rename task ${input.taskId} to an empty title`);
+    }
+    this.updateTask(input.taskId, (task) => ({ ...task, title: value, updatedAtMs: nowMs() }));
+  }
+
+  async renameBranch(input: TaskWorkbenchRenameInput): Promise<void> {
+    const value = input.value.trim();
+    if (!value) {
+      throw new Error(`Cannot rename branch for task ${input.taskId} to an empty value`);
+    }
+    this.updateTask(input.taskId, (task) => ({ ...task, branch: value, updatedAtMs: nowMs() }));
+  }
+
+  async archiveTask(input: TaskWorkbenchSelectInput): Promise<void> {
+    this.updateTask(input.taskId, (task) => ({ ...task, status: "archived", updatedAtMs: nowMs() }));
+  }
+
+  async publishPr(input: TaskWorkbenchSelectInput): Promise<void> {
+    const nextPrNumber = Math.max(0, ...this.snapshot.tasks.map((task) => task.pullRequest?.number ?? 0)) + 1;
+    this.updateTask(input.taskId, (task) => ({
+      ...task,
+      updatedAtMs: nowMs(),
+      pullRequest: { number: nextPrNumber, status: "ready" },
+    }));
+  }
+
+  async revertFile(input: TaskWorkbenchDiffInput): Promise<void> {
+    this.updateTask(input.taskId, (task) => {
+      const file = task.fileChanges.find((entry) => entry.path === input.path);
+      const nextDiffs = { ...task.diffs };
+      delete nextDiffs[input.path];
+
+      return {
+        ...task,
+        fileChanges: task.fileChanges.filter((entry) => entry.path !== input.path),
+        diffs: nextDiffs,
+        fileTree: file?.type === "A" ? removeFileTreePath(task.fileTree, input.path) : task.fileTree,
+      };
+    });
+  }
+
+  async updateDraft(input: TaskWorkbenchUpdateDraftInput): Promise<void> {
+    this.assertTab(input.taskId, input.tabId);
+    this.updateTask(input.taskId, (task) => ({
+      ...task,
+      updatedAtMs: nowMs(),
+      tabs: task.tabs.map((tab) =>
+        tab.id === input.tabId
+          ? {
+              ...tab,
+              draft: {
+                text: input.text,
+                attachments: input.attachments,
+                updatedAtMs: nowMs(),
+              },
+            }
+          : tab,
+      ),
+    }));
+  }
+
+  async sendMessage(input: TaskWorkbenchSendMessageInput): Promise<void> {
+    const text = input.text.trim();
+    if (!text) {
+      throw new Error(`Cannot send an empty mock prompt for task ${input.taskId}`);
+    }
+
+    this.assertTab(input.taskId, input.tabId);
+    const startedAtMs = nowMs();
+
+    this.updateTask(input.taskId, (currentTask) => {
+      const isFirstOnTask = currentTask.status === "new";
+      const newTitle = isFirstOnTask ? (text.length > 50 ? `${text.slice(0, 47)}...` : text) : currentTask.title;
+      const newBranch = isFirstOnTask ? `feat/${slugify(newTitle)}` : currentTask.branch;
+      const userMessageLines = [text, ...input.attachments.map((attachment) => `@ ${attachment.filePath}:${attachment.lineNumber}`)];
+      const userEvent = buildTranscriptEvent({
+        sessionId: input.tabId,
+        sender: "client",
+        createdAt: startedAtMs,
+        eventIndex: candidateEventIndex(currentTask, input.tabId),
+        payload: {
+          method: "session/prompt",
+          params: {
+            prompt: userMessageLines.map((line) => ({ type: "text", text: line })),
+          },
+        },
+      });
+
+      return {
+        ...currentTask,
+        title: newTitle,
+        branch: newBranch,
+        status: "running",
+        updatedAtMs: startedAtMs,
+        tabs: currentTask.tabs.map((candidate) =>
+          candidate.id === input.tabId
+            ? {
+                ...candidate,
+                created: true,
+                status: "running",
+                unread: false,
+                thinkingSinceMs: startedAtMs,
+                draft: { text: "", attachments: [], updatedAtMs: startedAtMs },
+                transcript: [...candidate.transcript, userEvent],
+              }
+            : candidate,
+        ),
+      };
+    });
+
+    const existingTimer = this.pendingTimers.get(input.tabId);
+    if (existingTimer) {
+      clearTimeout(existingTimer);
+    }
+
+    const timer = setTimeout(() => {
+      const task = this.requireTask(input.taskId);
+      const replyTab = this.requireTab(task, input.tabId);
+      const completedAtMs = nowMs();
+      const replyEvent = buildTranscriptEvent({
+        sessionId: input.tabId,
+        sender: "agent",
+        createdAt: completedAtMs,
+        eventIndex: candidateEventIndex(task, input.tabId),
+        payload: {
+          result: {
+            text: randomReply(),
+            durationMs: completedAtMs - startedAtMs,
+          },
+        },
+      });
+
+      this.updateTask(input.taskId, (currentTask) => {
+        const updatedTabs = currentTask.tabs.map((candidate) => {
+          if (candidate.id !== input.tabId) {
+            return candidate;
+          }
+
+          return {
+            ...candidate,
+            status: "idle" as const,
+            thinkingSinceMs: null,
+            unread: true,
+            transcript: [...candidate.transcript, replyEvent],
+          };
+        });
+        const anyRunning = updatedTabs.some((candidate) => candidate.status === "running");
+
+        return {
+          ...currentTask,
+          updatedAtMs: completedAtMs,
+          tabs: updatedTabs,
+          status: currentTask.status === "archived" ? "archived" : anyRunning ? "running" : "idle",
+        };
+      });
+
+      this.pendingTimers.delete(input.tabId);
+    }, 2_500);
+
+    this.pendingTimers.set(input.tabId, timer);
+  }
+
+  async stopAgent(input: TaskWorkbenchTabInput): Promise<void> {
+    this.assertTab(input.taskId, input.tabId);
+    const existing = this.pendingTimers.get(input.tabId);
+    if (existing) {
+      clearTimeout(existing);
+      this.pendingTimers.delete(input.tabId);
+    }
+
+    this.updateTask(input.taskId, (currentTask) => {
+      const updatedTabs = currentTask.tabs.map((candidate) =>
+        candidate.id === input.tabId ? { ...candidate, status: "idle" as const, thinkingSinceMs: null } : candidate,
+      );
+      const anyRunning = updatedTabs.some((candidate) => candidate.status === "running");
+
+      return {
+        ...currentTask,
+        updatedAtMs: nowMs(),
+        tabs: updatedTabs,
+        status: currentTask.status === "archived" ? "archived" : anyRunning ? "running" : "idle",
+      };
+    });
+  }
+
+  async setSessionUnread(input: TaskWorkbenchSetSessionUnreadInput): Promise<void> {
+    this.updateTask(input.taskId, (currentTask) => ({
+      ...currentTask,
+      tabs: currentTask.tabs.map((candidate) => (candidate.id === input.tabId ? { ...candidate, unread: input.unread } : candidate)),
+    }));
+  }
+
+  async renameSession(input: TaskWorkbenchRenameSessionInput): Promise<void> {
+    const title = input.title.trim();
+    if (!title) {
+      throw new Error(`Cannot rename session ${input.tabId} to an empty title`);
+    }
+    this.updateTask(input.taskId, (currentTask) => ({
+      ...currentTask,
+      tabs: currentTask.tabs.map((candidate) => (candidate.id === input.tabId ? { ...candidate, sessionName: title } : candidate)),
+    }));
+  }
+
+  async closeTab(input: TaskWorkbenchTabInput): Promise<void> {
+    this.updateTask(input.taskId, (currentTask) => {
+      if (currentTask.tabs.length <= 1) {
+        return currentTask;
+      }
+
+      return {
+        ...currentTask,
+        tabs: currentTask.tabs.filter((candidate) => candidate.id !== input.tabId),
+      };
+    });
+  }
+
+  async addTab(input: TaskWorkbenchSelectInput): Promise<TaskWorkbenchAddTabResponse> {
+    this.assertTask(input.taskId);
+    const nextTab: AgentTab = {
+      id: uid(),
+      sessionId: null,
+      sessionName: `Session ${this.requireTask(input.taskId).tabs.length + 1}`,
+      agent: "Claude",
+      model: "claude-sonnet-4",
+      status: "idle",
+      thinkingSinceMs: null,
+      unread: false,
+      created: false,
+      draft: { text: "", attachments: [], updatedAtMs: null },
+      transcript: [],
+    };
+
+    this.updateTask(input.taskId, (currentTask) => ({
+      ...currentTask,
+      updatedAtMs: nowMs(),
+      tabs: [...currentTask.tabs, nextTab],
+    }));
+    return { tabId: nextTab.id };
+  }
+
+  async changeModel(input: TaskWorkbenchChangeModelInput): Promise<void> {
+    const group = MODEL_GROUPS.find((candidate) => candidate.models.some((entry) => entry.id === input.model));
+    if (!group) {
+      throw new Error(`Unable to resolve model provider for ${input.model}`);
+    }
+
+    this.updateTask(input.taskId, (currentTask) => ({
+      ...currentTask,
+      tabs: currentTask.tabs.map((candidate) =>
+        candidate.id === input.tabId ? { ...candidate, model: input.model, agent: providerAgent(group.provider) } : candidate,
+      ),
+    }));
+  }
+
+  private updateState(updater: (current: TaskWorkbenchSnapshot) => TaskWorkbenchSnapshot): void {
+    const nextSnapshot = updater(this.snapshot);
+    this.snapshot = {
+      ...nextSnapshot,
+      projects: groupWorkbenchProjects(nextSnapshot.repos, nextSnapshot.tasks),
+    };
+    this.notify();
+  }
+
+  private updateTask(taskId: string, updater: (task: Task) => Task): void {
+    this.assertTask(taskId);
+    this.updateState((current) => ({
+      ...current,
+      tasks: current.tasks.map((task) => (task.id === taskId ? updater(task) : task)),
+    }));
+  }
+
+  private notify(): void {
+    for (const listener of this.listeners) {
+      listener();
+    }
+  }
+
+  private assertTask(taskId: string): void {
+    this.requireTask(taskId);
+  }
+
+  private assertTab(taskId: string, tabId: string): void {
+    const task = this.requireTask(taskId);
+    this.requireTab(task, tabId);
+  }
+
+  private requireTask(taskId: string): Task {
+    const task = this.snapshot.tasks.find((candidate) => candidate.id === taskId);
+    if (!task) {
+      throw new Error(`Unable to find mock task ${taskId}`);
+    }
+    return task;
+  }
+
+  private requireTab(task: Task, tabId: string): AgentTab {
+    const tab = task.tabs.find((candidate) => candidate.id === tabId);
+    if (!tab) {
+      throw new Error(`Unable to find mock tab ${tabId} in task ${task.id}`);
+    }
+    return tab;
+  }
+}
+
+function candidateEventIndex(task: Task, tabId: string): number {
+  const tab = task.tabs.find((candidate) => candidate.id === tabId);
+  return (tab?.transcript.length ?? 0) + 1;
+}
+
+let sharedMockWorkbenchClient: TaskWorkbenchClient | null = null;
+
+export function getSharedMockWorkbenchClient(): TaskWorkbenchClient {
+  if (!sharedMockWorkbenchClient) {
+    sharedMockWorkbenchClient = new MockWorkbenchStore();
+  }
+  return sharedMockWorkbenchClient;
+}