feat(server): add Claude /rewind command support

packages/server/src/server/agent/providers/claude-agent-commands.e2e.test.ts

@@ -51,6 +51,7 @@ describe("claude agent commands E2E", () => {
     // These are skills that come from CLAUDE.md configurations
     // At minimum we should have some commands available
     expect(commandNames.length).toBeGreaterThan(0);
+    expect(commandNames).toContain("rewind");
   }, 60000);
 
   test("returns error for non-existent agent", async () => {

packages/server/src/server/agent/providers/claude-agent-commands.test.ts

@@ -85,6 +85,7 @@ const hasClaudeCredentials =
       // Should have at least one command (skills are loaded from user/project settings)
       // The exact commands depend on what skills are configured
       expect(commands.length).toBeGreaterThan(0);
+      expect(commandNames).toContain("rewind");
 
       await session.close();
     }, 30000);

packages/server/src/server/agent/providers/claude-agent.test.ts

@@ -789,6 +789,63 @@ async function startAgentMcpServer(): Promise<AgentMcpServerHandle> {
     120_000
   );
 
+  test(
+    "supports /rewind by reverting the latest file changes",
+    async () => {
+      const cwd = tmpCwd();
+      const client = new ClaudeAgentClient({ logger });
+      const config = buildConfig(cwd, { maxThinkingTokens: 2048 });
+      const session = await client.createSession(config);
+      const filePath = path.join(cwd, "rewind-target.txt");
+      const tokenA = `REWIND_A_${Date.now().toString(36)}`;
+      const tokenB = `REWIND_B_${Date.now().toString(36)}`;
+
+      const runPrompt = async (prompt: string): Promise<void> => {
+        for await (const event of session.stream(prompt)) {
+          await autoApprove(session, event);
+          if (event.type === "turn_failed") {
+            throw new Error(event.error);
+          }
+          if (event.type === "turn_completed") {
+            break;
+          }
+        }
+      };
+
+      try {
+        await runPrompt(
+          [
+            "Create a file named rewind-target.txt in the current directory.",
+            `Set the file content to exactly: ${tokenA}`,
+            "Do not add extra text or commentary.",
+          ].join(" ")
+        );
+        expect(existsSync(filePath)).toBe(true);
+        expect(readFileSync(filePath, "utf8")).toContain(tokenA);
+
+        await runPrompt(
+          [
+            "Edit rewind-target.txt in place.",
+            `Replace the entire file content with exactly: ${tokenB}`,
+            "Do not add extra text or commentary.",
+          ].join(" ")
+        );
+        expect(readFileSync(filePath, "utf8")).toContain(tokenB);
+
+        const rewind = await session.run("/rewind");
+        expect(rewind.finalText.toLowerCase()).toContain("rewound");
+
+        const contentAfterRewind = readFileSync(filePath, "utf8");
+        expect(contentAfterRewind).toContain(tokenA);
+        expect(contentAfterRewind).not.toContain(tokenB);
+      } finally {
+        await session.close();
+        rmSync(cwd, { recursive: true, force: true });
+      }
+    },
+    240_000
+  );
+
   test(
     "resumes a persisted session with context preserved",
     async () => {

packages/server/src/server/agent/providers/claude-agent.ts

@@ -212,6 +212,21 @@ const VALID_CLAUDE_MODES = new Set(
   DEFAULT_MODES.map((mode) => mode.id)
 );
 
+const REWIND_COMMAND_NAME = "rewind";
+const REWIND_COMMAND: AgentSlashCommand = {
+  name: REWIND_COMMAND_NAME,
+  description: "Rewind tracked files to a previous user message",
+  argumentHint: "[user_message_uuid]",
+};
+const UUID_PATTERN =
+  /^[0-9a-f]{8}-[0-9a-f]{4}-[1-8][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;
+
+type SlashCommandInvocation = {
+  commandName: string;
+  args?: string;
+  rawInput: string;
+};
+
 // Orchestrator instructions moved to shared module.
 type ClaudeAgentConfig = AgentSessionConfig & { provider: "claude" };
 
@@ -672,6 +687,7 @@ class ClaudeAgentSession implements AgentSession {
   private activeSidechains = new Map<string, string>();
   private compacting = false;
   private queryRestartNeeded = false;
+  private userMessageIds: string[] = [];
 
   constructor(
     config: ClaudeAgentConfig,
@@ -787,6 +803,12 @@ class ClaudeAgentSession implements AgentSession {
     // Reset cancel flag at the start of each turn to prevent stale state from previous turns
     this.turnCancelRequested = false;
 
+    const slashCommand = this.resolveSlashCommandInvocation(prompt);
+    if (slashCommand?.commandName === REWIND_COMMAND_NAME) {
+      yield* this.streamRewindCommand(slashCommand);
+      return;
+    }
+
     const sdkMessage = this.toSdkUserMessage(prompt);
     const queue = new Pushable<AgentStreamEvent>();
     this.eventQueue = queue;
@@ -1007,11 +1029,284 @@ class ClaudeAgentSession implements AgentSession {
   async listCommands(): Promise<AgentSlashCommand[]> {
     const q = await this.ensureQuery();
     const commands = await q.supportedCommands();
-    return commands.map((cmd) => ({
-      name: cmd.name,
-      description: cmd.description,
-      argumentHint: cmd.argumentHint,
-    }));
+    const commandMap = new Map<string, AgentSlashCommand>();
+    for (const cmd of commands) {
+      if (!commandMap.has(cmd.name)) {
+        commandMap.set(cmd.name, {
+          name: cmd.name,
+          description: cmd.description,
+          argumentHint: cmd.argumentHint,
+        });
+      }
+    }
+    if (!commandMap.has(REWIND_COMMAND_NAME)) {
+      commandMap.set(REWIND_COMMAND_NAME, REWIND_COMMAND);
+    }
+    return Array.from(commandMap.values()).sort((a, b) =>
+      a.name.localeCompare(b.name)
+    );
+  }
+
+  private resolveSlashCommandInvocation(
+    prompt: AgentPromptInput
+  ): SlashCommandInvocation | null {
+    if (typeof prompt !== "string") {
+      return null;
+    }
+    const parsed = this.parseSlashCommandInput(prompt);
+    if (!parsed) {
+      return null;
+    }
+    return parsed.commandName === REWIND_COMMAND_NAME ? parsed : null;
+  }
+
+  private parseSlashCommandInput(text: string): SlashCommandInvocation | null {
+    const trimmed = text.trim();
+    if (!trimmed.startsWith("/") || trimmed.length <= 1) {
+      return null;
+    }
+    const withoutPrefix = trimmed.slice(1);
+    const firstWhitespaceIdx = withoutPrefix.search(/\s/);
+    const commandName =
+      firstWhitespaceIdx === -1
+        ? withoutPrefix
+        : withoutPrefix.slice(0, firstWhitespaceIdx);
+    if (!commandName || commandName.includes("/")) {
+      return null;
+    }
+    const rawArgs =
+      firstWhitespaceIdx === -1
+        ? ""
+        : withoutPrefix.slice(firstWhitespaceIdx + 1).trim();
+    return rawArgs.length > 0
+      ? { commandName, args: rawArgs, rawInput: trimmed }
+      : { commandName, rawInput: trimmed };
+  }
+
+  private async *streamRewindCommand(
+    invocation: SlashCommandInvocation
+  ): AsyncGenerator<AgentStreamEvent> {
+    yield { type: "turn_started", provider: "claude" };
+    yield {
+      type: "timeline",
+      provider: "claude",
+      item: { type: "user_message", text: invocation.rawInput },
+    };
+
+    try {
+      const rewindAttempt = await this.attemptRewind(invocation.args);
+      if (!rewindAttempt.messageId || !rewindAttempt.result) {
+        yield {
+          type: "turn_failed",
+          provider: "claude",
+          error:
+            rewindAttempt.error ??
+            "No prior user message available to rewind. Use /rewind <user_message_uuid>.",
+        };
+        return;
+      }
+      yield {
+        type: "timeline",
+        provider: "claude",
+        item: {
+          type: "assistant_message",
+          text: this.buildRewindSuccessMessage(
+            rewindAttempt.messageId,
+            rewindAttempt.result
+          ),
+        },
+      };
+      yield { type: "turn_completed", provider: "claude" };
+    } catch (error) {
+      yield {
+        type: "turn_failed",
+        provider: "claude",
+        error:
+          error instanceof Error
+            ? error.message
+            : "Failed to rewind tracked files",
+      };
+    }
+  }
+
+  private buildRewindSuccessMessage(
+    targetUserMessageId: string,
+    rewindResult: { filesChanged?: string[]; insertions?: number; deletions?: number }
+  ): string {
+    const fileCount = Array.isArray(rewindResult.filesChanged)
+      ? rewindResult.filesChanged.length
+      : undefined;
+    const stats: string[] = [];
+    if (typeof fileCount === "number") {
+      stats.push(`${fileCount} file${fileCount === 1 ? "" : "s"}`);
+    }
+    if (typeof rewindResult.insertions === "number") {
+      stats.push(`${rewindResult.insertions} insertions`);
+    }
+    if (typeof rewindResult.deletions === "number") {
+      stats.push(`${rewindResult.deletions} deletions`);
+    }
+    if (stats.length > 0) {
+      return `Rewound tracked files to message ${targetUserMessageId} (${stats.join(", ")}).`;
+    }
+    return `Rewound tracked files to message ${targetUserMessageId}.`;
+  }
+
+  private async attemptRewind(
+    args: string | undefined
+  ): Promise<{
+    messageId: string | null;
+    result?: { filesChanged?: string[]; insertions?: number; deletions?: number };
+    error?: string;
+  }> {
+    if (typeof args === "string" && args.trim().length > 0) {
+      const candidate = args.trim().split(/\s+/)[0] ?? "";
+      if (!UUID_PATTERN.test(candidate)) {
+        return {
+          messageId: null,
+          error:
+            "Invalid message UUID. Usage: /rewind <user_message_uuid> or /rewind",
+        };
+      }
+      const rewindResult = await this.rewindFilesOnce(candidate);
+      if (rewindResult.canRewind) {
+        return { messageId: candidate, result: rewindResult };
+      }
+      return {
+        messageId: null,
+        error:
+          rewindResult.error ??
+          `No file checkpoint found for message ${candidate}.`,
+      };
+    }
+
+    const candidates = this.getRewindCandidateUserMessageIds();
+    if (candidates.length === 0) {
+      return {
+        messageId: null,
+        error:
+          "No prior user message available to rewind. Use /rewind <user_message_uuid>.",
+      };
+    }
+
+    let lastError: string | undefined;
+    for (const candidate of candidates) {
+      try {
+        const rewindResult = await this.rewindFilesOnce(candidate);
+        if (rewindResult.canRewind) {
+          return { messageId: candidate, result: rewindResult };
+        }
+        if (rewindResult.error) {
+          lastError = rewindResult.error;
+        }
+      } catch (error) {
+        lastError =
+          error instanceof Error
+            ? error.message
+            : "Failed to rewind tracked files.";
+      }
+    }
+
+    return {
+      messageId: null,
+      error:
+        lastError ??
+        "No rewind checkpoints are currently available for this session.",
+    };
+  }
+
+  private async rewindFilesOnce(messageId: string): Promise<{
+    canRewind: boolean;
+    error?: string;
+    filesChanged?: string[];
+    insertions?: number;
+    deletions?: number;
+  }> {
+    try {
+      const query = await this.ensureFreshQuery();
+      return await query.rewindFiles(messageId, { dryRun: false });
+    } catch (error) {
+      // The Claude SDK transport can close after a rewind call.
+      // If that happens, mark the query stale so a follow-up attempt uses a fresh query.
+      this.queryRestartNeeded = true;
+      throw error;
+    }
+  }
+
+  private async ensureFreshQuery(): Promise<Query> {
+    if (this.query) {
+      this.queryRestartNeeded = true;
+    }
+    return this.ensureQuery();
+  }
+
+  private getRewindCandidateUserMessageIds(): string[] {
+    const candidates: string[] = [];
+    const pushUnique = (value: string | null | undefined) => {
+      if (
+        typeof value === "string" &&
+        value.length > 0 &&
+        !candidates.includes(value)
+      ) {
+        candidates.push(value);
+      }
+    };
+
+    const historyIds = this.readUserMessageIdsFromHistoryFile();
+    for (let idx = historyIds.length - 1; idx >= 0; idx -= 1) {
+      pushUnique(historyIds[idx]);
+    }
+    for (let idx = this.persistedHistory.length - 1; idx >= 0; idx -= 1) {
+      const item = this.persistedHistory[idx];
+      if (item?.type === "user_message") {
+        pushUnique(item.messageId);
+      }
+    }
+    for (let idx = this.userMessageIds.length - 1; idx >= 0; idx -= 1) {
+      pushUnique(this.userMessageIds[idx]);
+    }
+
+    return candidates;
+  }
+
+  private readUserMessageIdsFromHistoryFile(): string[] {
+    if (!this.claudeSessionId) {
+      return [];
+    }
+    const historyPath = this.resolveHistoryPath(this.claudeSessionId);
+    if (!historyPath || !fs.existsSync(historyPath)) {
+      return [];
+    }
+    try {
+      const ids: string[] = [];
+      const content = fs.readFileSync(historyPath, "utf8");
+      for (const line of content.split(/\n+/)) {
+        const trimmed = line.trim();
+        if (!trimmed) continue;
+        try {
+          const entry = JSON.parse(trimmed);
+          if (entry?.type === "user" && typeof entry.uuid === "string") {
+            ids.push(entry.uuid);
+          }
+        } catch {
+          // ignore malformed lines
+        }
+      }
+      return ids;
+    } catch {
+      return [];
+    }
+  }
+
+  private rememberUserMessageId(messageId: string | null | undefined): void {
+    if (typeof messageId !== "string" || messageId.length === 0) {
+      return;
+    }
+    const last = this.userMessageIds[this.userMessageIds.length - 1];
+    if (last === messageId) {
+      return;
+    }
+    this.userMessageIds.push(messageId);
   }
 
   private async primeSelectableModelIds(query: Query): Promise<void> {
@@ -1095,6 +1390,8 @@ class ClaudeAgentSession implements AgentSession {
         MCP_TIMEOUT: "600000",
         MCP_TOOL_TIMEOUT: "600000",
       },
+      // Required for provider-level /rewind support.
+      enableFileCheckpointing: true,
       // If we have a session ID from a previous query (e.g., after interrupt),
       // resume that session to continue the conversation history.
       ...(this.claudeSessionId ? { resume: this.claudeSessionId } : {}),
@@ -1174,6 +1471,9 @@ class ClaudeAgentSession implements AgentSession {
       content.push({ type: "text", text: prompt });
     }
 
+    const messageId = randomUUID();
+    this.rememberUserMessageId(messageId);
+
     return {
       type: "user",
       message: {
@@ -1181,6 +1481,7 @@ class ClaudeAgentSession implements AgentSession {
         content,
       },
       parent_tool_use_id: null,
+      uuid: messageId,
       session_id: this.claudeSessionId ?? "",
     };
   }
@@ -1426,17 +1727,34 @@ class ClaudeAgentSession implements AgentSession {
           this.compacting = false;
           break;
         }
+        const messageId =
+          typeof message.uuid === "string" && message.uuid.length > 0
+            ? message.uuid
+            : undefined;
+        this.rememberUserMessageId(messageId);
         const content = message.message?.content;
         if (typeof content === "string" && content.length > 0) {
           // String content from user messages (e.g., local command output)
           events.push({
             type: "timeline",
-            item: { type: "user_message", text: content },
+            item: {
+              type: "user_message",
+              text: content,
+              ...(messageId ? { messageId } : {}),
+            },
             provider: "claude",
           });
         } else if (Array.isArray(content)) {
           const timelineItems = this.mapBlocksToTimeline(content, { turnContext });
           for (const item of timelineItems) {
+            if (item.type === "user_message" && messageId && !item.messageId) {
+              events.push({
+                type: "timeline",
+                item: { ...item, messageId },
+                provider: "claude",
+              });
+              continue;
+            }
             events.push({ type: "timeline", item, provider: "claude" });
           }
         }
@@ -1723,6 +2041,9 @@ class ClaudeAgentSession implements AgentSession {
           if (entry.isSidechain) {
             continue;
           }
+          if (entry.type === "user" && typeof entry.uuid === "string") {
+            this.rememberUserMessageId(entry.uuid);
+          }
           const items = this.convertHistoryEntry(entry);
           if (items.length > 0) {
             timeline.push(...items);
@@ -2300,9 +2621,14 @@ export function convertClaudeHistoryEntry(
   if (entry.type === "user") {
     const text = extractUserMessageText(content);
     if (text) {
+      const messageId =
+        typeof entry.uuid === "string" && entry.uuid.length > 0
+          ? entry.uuid
+          : undefined;
       timeline.push({
         type: "user_message",
         text,
+        ...(messageId ? { messageId } : {}),
       });
     }
   }

packages/server/src/server/agent/providers/claude-agent.voice-history-regression.test.ts

@@ -12,6 +12,7 @@ import type {
 
 const sdkMocks = vi.hoisted(() => ({
   query: vi.fn(),
+  lastQuery: null as ReturnType<typeof buildSdkQueryMock> | null,
 }));
 
 vi.mock("@anthropic-ai/claude-agent-sdk", () => ({
@@ -65,6 +66,7 @@ function buildSdkQueryMock() {
     setModel: vi.fn(async () => undefined),
     supportedModels: vi.fn(async () => [{ value: "opus", displayName: "Opus" }]),
     supportedCommands: vi.fn(async () => []),
+    rewindFiles: vi.fn(async () => ({ canRewind: true })),
   };
 }
 
@@ -91,7 +93,11 @@ describe("ClaudeAgentSession history replay regression", () => {
   let previousClaudeConfigDir: string | undefined;
 
   beforeEach(() => {
-    sdkMocks.query.mockImplementation(() => buildSdkQueryMock());
+    sdkMocks.query.mockImplementation(() => {
+      const mock = buildSdkQueryMock();
+      sdkMocks.lastQuery = mock;
+      return mock;
+    });
 
     tempRoot = mkdtempSync(path.join(os.tmpdir(), "claude-history-regression-"));
     cwd = path.join(tempRoot, "repo");
@@ -107,6 +113,7 @@ describe("ClaudeAgentSession history replay regression", () => {
       [
         JSON.stringify({
           type: "user",
+          uuid: "history-user-uuid",
           sessionId: "history-session",
           cwd,
           message: {
@@ -133,6 +140,7 @@ describe("ClaudeAgentSession history replay regression", () => {
 
   afterEach(() => {
     sdkMocks.query.mockReset();
+    sdkMocks.lastQuery = null;
     if (previousClaudeConfigDir === undefined) {
       delete process.env.CLAUDE_CONFIG_DIR;
     } else {
@@ -206,4 +214,67 @@ describe("ClaudeAgentSession history replay regression", () => {
     expect(timelineText).toContain(HISTORY_USER_MARKER);
     expect(timelineText).toContain(HISTORY_ASSISTANT_MARKER);
   });
+
+  test("listCommands includes rewind command", async () => {
+    const logger = createTestLogger();
+    const client = new ClaudeAgentClient({ logger });
+    const handle: AgentPersistenceHandle = {
+      provider: "claude",
+      sessionId: "history-session",
+      nativeHandle: "history-session",
+      metadata: {
+        provider: "claude",
+        cwd,
+      },
+    };
+
+    const session = await client.resumeSession(handle, { cwd });
+    try {
+      const commands = await session.listCommands?.();
+      expect(commands?.some((command) => command.name === "rewind")).toBe(true);
+    } finally {
+      await session.close();
+    }
+  });
+
+  test("slash /rewind uses latest user message id from persisted history", async () => {
+    const logger = createTestLogger();
+    const client = new ClaudeAgentClient({ logger });
+    const handle: AgentPersistenceHandle = {
+      provider: "claude",
+      sessionId: "history-session",
+      nativeHandle: "history-session",
+      metadata: {
+        provider: "claude",
+        cwd,
+      },
+    };
+
+    const session = await client.resumeSession(handle, { cwd });
+    const events: AgentStreamEvent[] = [];
+
+    try {
+      for await (const event of session.stream("/rewind")) {
+        events.push(event);
+        if (
+          event.type === "turn_completed" ||
+          event.type === "turn_failed" ||
+          event.type === "turn_canceled"
+        ) {
+          break;
+        }
+      }
+    } finally {
+      await session.close();
+    }
+
+    expect(events.some((event) => event.type === "turn_started")).toBe(true);
+    expect(events.some((event) => event.type === "turn_completed")).toBe(true);
+    expect(sdkMocks.lastQuery).toBeTruthy();
+    expect(sdkMocks.lastQuery?.rewindFiles).toHaveBeenCalledTimes(1);
+    expect(sdkMocks.lastQuery?.rewindFiles).toHaveBeenCalledWith(
+      "history-user-uuid",
+      { dryRun: false }
+    );
+  });
 });

packages/server/src/server/test-utils/fake-agent-client.ts

@@ -570,7 +570,19 @@ class FakeAgentSession implements AgentSession {
       return commands;
     }
 
-    // claude/opencode: keep stable/deterministic.
+    // Keep deterministic defaults for non-codex providers.
+    if (this.providerName === "claude") {
+      return [
+        { name: "help", description: "Help", argumentHint: "" },
+        { name: "context", description: "Context", argumentHint: "" },
+        {
+          name: "rewind",
+          description: "Rewind tracked files to a previous user message",
+          argumentHint: "[user_message_uuid]",
+        },
+      ];
+    }
+
     return [
       { name: "help", description: "Help", argumentHint: "" },
       { name: "context", description: "Context", argumentHint: "" },