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Rewind file changes with checkpointing

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Rewind file changes with checkpointing

Track file changes during agent sessions and restore files to any previous state

File checkpointing tracks file modifications made through the Write, Edit, and NotebookEdit tools during an agent session, allowing you to rewind files to any previous state. Want to try it out? Jump to the interactive example.

With checkpointing, you can:

Only changes made through the Write, Edit, and NotebookEdit tools are tracked. Changes made through Bash commands (like echo > file.txt or sed -i) are not captured by the checkpoint system.

How checkpointing works

When you enable file checkpointing, the SDK creates backups of files before modifying them through the Write, Edit, or NotebookEdit tools. User messages in the response stream include a checkpoint UUID that you can use as a restore point.

Checkpoint works with these built-in tools that the agent uses to modify files:

Tool Description
Write Creates a new file or overwrites an existing file with new content
Edit Makes targeted edits to specific parts of an existing file
NotebookEdit Modifies cells in Jupyter notebooks (.ipynb files)

File rewinding restores files on disk to a previous state. It does not rewind the conversation itself. The conversation history and context remain intact after calling rewindFiles() (TypeScript) or rewind_files() (Python).

The checkpoint system tracks:

When you rewind to a checkpoint, created files are deleted and modified files are restored to their content at that point.

Implement checkpointing

To use file checkpointing, enable it in your options, capture checkpoint UUIDs from the response stream, then call rewindFiles() (TypeScript) or rewind_files() (Python) when you need to restore.

The following example shows the complete flow: enable checkpointing, capture the checkpoint UUID and session ID from the response stream, then resume the session later to rewind files. Each step is explained in detail below.

```python Python theme={null} import asyncio from claude_agent_sdk import ( ClaudeSDKClient, ClaudeAgentOptions, UserMessage, ResultMessage, )

async def main(): # Step 1: Enable checkpointing options = ClaudeAgentOptions( enable_file_checkpointing=True, permission_mode="acceptEdits", # Auto-accept file edits without prompting extra_args={ "replay-user-messages": None }, # Required to receive checkpoint UUIDs in the response stream )

  checkpoint_id = None
  session_id = None

  # Run the query and capture checkpoint UUID and session ID
  async with ClaudeSDKClient(options) as client:
      await client.query("Refactor the authentication module")

      # Step 2: Capture checkpoint UUID from the first user message
      async for message in client.receive_response():
          if isinstance(message, UserMessage) and message.uuid and not checkpoint_id:
              checkpoint_id = message.uuid
          if isinstance(message, ResultMessage) and not session_id:
              session_id = message.session_id

  # Step 3: Later, rewind by resuming the session with an empty prompt
  if checkpoint_id and session_id:
      async with ClaudeSDKClient(
          ClaudeAgentOptions(enable_file_checkpointing=True, resume=session_id)
      ) as client:
          await client.query("")  # Empty prompt to open the connection
          async for message in client.receive_response():
              await client.rewind_files(checkpoint_id)
              break
      print(f"Rewound to checkpoint: {checkpoint_id}")

asyncio.run(main()) ```

```typescript TypeScript theme={null} import { query } from "@anthropic-ai/claude-agent-sdk";

async function main() { // Step 1: Enable checkpointing const opts = { enableFileCheckpointing: true, permissionMode: "acceptEdits" as const, // Auto-accept file edits without prompting extraArgs: { "replay-user-messages": null } // Required to receive checkpoint UUIDs in the response stream };

const response = query({
  prompt: "Refactor the authentication module",
  options: opts
});

let checkpointId: string | undefined;
let sessionId: string | undefined;

// Step 2: Capture checkpoint UUID from the first user message
for await (const message of response) {
  if (message.type === "user" && message.uuid && !checkpointId) {
    checkpointId = message.uuid;
  }
  if ("session_id" in message && !sessionId) {
    sessionId = message.session_id;
  }
}

// Step 3: Later, rewind by resuming the session with an empty prompt
if (checkpointId && sessionId) {
  const rewindQuery = query({
    prompt: "", // Empty prompt to open the connection
    options: { ...opts, resume: sessionId }
  });

  for await (const msg of rewindQuery) {
    await rewindQuery.rewindFiles(checkpointId);
    break;
  }
  console.log(`Rewound to checkpoint: ${checkpointId}`);
}

}

main(); ```

Configure your SDK options to enable checkpointing and receive checkpoint UUIDs:

| Option                   | Python                                      | TypeScript                                    | Description                                      |
| ------------------------ | ------------------------------------------- | --------------------------------------------- | ------------------------------------------------ |
| Enable checkpointing     | `enable_file_checkpointing=True`            | `enableFileCheckpointing: true`               | Tracks file changes for rewinding                |
| Receive checkpoint UUIDs | `extra_args={"replay-user-messages": None}` | `extraArgs: { 'replay-user-messages': null }` | Required to get user message UUIDs in the stream |

<CodeGroup>
  ```python Python theme={null}
  options = ClaudeAgentOptions(
      enable_file_checkpointing=True,
      permission_mode="acceptEdits",
      extra_args={"replay-user-messages": None},
  )

  async with ClaudeSDKClient(options) as client:
      await client.query("Refactor the authentication module")
  ```

  ```typescript TypeScript theme={null}
  const response = query({
    prompt: "Refactor the authentication module",
    options: {
      enableFileCheckpointing: true,
      permissionMode: "acceptEdits" as const,
      extraArgs: { "replay-user-messages": null }
    }
  });
  ```
</CodeGroup>

With the replay-user-messages option set (shown above), each user message in the response stream has a UUID that serves as a checkpoint.

For most use cases, capture the first user message UUID (`message.uuid`); rewinding to it restores all files to their original state. To store multiple checkpoints and rewind to intermediate states, see [Multiple restore points](#multiple-restore-points).

Capturing the session ID (`message.session_id`) is optional; you only need it if you want to rewind later, after the stream completes. If you're calling `rewindFiles()` immediately while still processing messages (as the example in [Checkpoint before risky operations](#checkpoint-before-risky-operations) does), you can skip capturing the session ID.

<CodeGroup>
  ```python Python theme={null}
  checkpoint_id = None
  session_id = None

  async for message in client.receive_response():
      # Update checkpoint on each user message (keeps the latest)
      if isinstance(message, UserMessage) and message.uuid:
          checkpoint_id = message.uuid
      # Capture session ID from the result message
      if isinstance(message, ResultMessage):
          session_id = message.session_id
  ```

  ```typescript TypeScript theme={null}
  let checkpointId: string | undefined;
  let sessionId: string | undefined;

  for await (const message of response) {
    // Update checkpoint on each user message (keeps the latest)
    if (message.type === "user" && message.uuid) {
      checkpointId = message.uuid;
    }
    // Capture session ID from any message that has it
    if ("session_id" in message) {
      sessionId = message.session_id;
    }
  }
  ```
</CodeGroup>

To rewind after the stream completes, resume the session with an empty prompt and call rewind_files() (Python) or rewindFiles() (TypeScript) with your checkpoint UUID. You can also rewind during the stream; see Checkpoint before risky operations for that pattern.

<CodeGroup>
  ```python Python theme={null}
  async with ClaudeSDKClient(
      ClaudeAgentOptions(enable_file_checkpointing=True, resume=session_id)
  ) as client:
      await client.query("")  # Empty prompt to open the connection
      async for message in client.receive_response():
          await client.rewind_files(checkpoint_id)
          break
  ```

  ```typescript TypeScript theme={null}
  const rewindQuery = query({
    prompt: "", // Empty prompt to open the connection
    options: { ...opts, resume: sessionId }
  });

  for await (const msg of rewindQuery) {
    await rewindQuery.rewindFiles(checkpointId);
    break;
  }
  ```
</CodeGroup>

If you capture the session ID and checkpoint ID, you can also rewind from the CLI:

```bash theme={null}
claude -p --resume <session-id> --rewind-files <checkpoint-uuid>
```

Common patterns

These patterns show different ways to capture and use checkpoint UUIDs depending on your use case.

Checkpoint before risky operations

This pattern keeps only the most recent checkpoint UUID, updating it before each agent turn. If something goes wrong during processing, you can immediately rewind to the last safe state and break out of the loop.

```python Python theme={null} import asyncio from claude_agent_sdk import ClaudeSDKClient, ClaudeAgentOptions, UserMessage

async def main(): options = ClaudeAgentOptions( enable_file_checkpointing=True, permission_mode="acceptEdits", extra_args={"replay-user-messages": None}, )

  safe_checkpoint = None

  async with ClaudeSDKClient(options) as client:
      await client.query("Refactor the authentication module")

      async for message in client.receive_response():
          # Update checkpoint before each agent turn starts
          # This overwrites the previous checkpoint. Only keep the latest
          if isinstance(message, UserMessage) and message.uuid:
              safe_checkpoint = message.uuid

          # Decide when to revert based on your own logic
          # For example: error detection, validation failure, or user input
          if your_revert_condition and safe_checkpoint:
              await client.rewind_files(safe_checkpoint)
              # Exit the loop after rewinding, files are restored
              break

asyncio.run(main()) ```

```typescript TypeScript theme={null} import { query } from "@anthropic-ai/claude-agent-sdk";

async function main() { const response = query({ prompt: "Refactor the authentication module", options: { enableFileCheckpointing: true, permissionMode: "acceptEdits" as const, extraArgs: { "replay-user-messages": null } } });

let safeCheckpoint: string | undefined;

for await (const message of response) {
  // Update checkpoint before each agent turn starts
  // This overwrites the previous checkpoint. Only keep the latest
  if (message.type === "user" && message.uuid) {
    safeCheckpoint = message.uuid;
  }

  // Decide when to revert based on your own logic
  // For example: error detection, validation failure, or user input
  if (yourRevertCondition && safeCheckpoint) {
    await response.rewindFiles(safeCheckpoint);
    // Exit the loop after rewinding, files are restored
    break;
  }
}

}

main(); ```

Multiple restore points

If Claude makes changes across multiple turns, you might want to rewind to a specific point rather than all the way back. For example, if Claude refactors a file in turn one and adds tests in turn two, you might want to keep the refactor but undo the tests.

This pattern stores all checkpoint UUIDs in an array with metadata. After the session completes, you can rewind to any previous checkpoint:

```python Python theme={null} import asyncio from dataclasses import dataclass from datetime import datetime from claude_agent_sdk import ( ClaudeSDKClient, ClaudeAgentOptions, UserMessage, ResultMessage, )

# Store checkpoint metadata for better tracking @dataclass class Checkpoint: id: str description: str timestamp: datetime

async def main(): options = ClaudeAgentOptions( enable_file_checkpointing=True, permission_mode="acceptEdits", extra_args={"replay-user-messages": None}, )

  checkpoints = []
  session_id = None

  async with ClaudeSDKClient(options) as client:
      await client.query("Refactor the authentication module")

      async for message in client.receive_response():
          if isinstance(message, UserMessage) and message.uuid:
              checkpoints.append(
                  Checkpoint(
                      id=message.uuid,
                      description=f"After turn {len(checkpoints) + 1}",
                      timestamp=datetime.now(),
                  )
              )
          if isinstance(message, ResultMessage) and not session_id:
              session_id = message.session_id

  # Later: rewind to any checkpoint by resuming the session
  if checkpoints and session_id:
      target = checkpoints[0]  # Pick any checkpoint
      async with ClaudeSDKClient(
          ClaudeAgentOptions(enable_file_checkpointing=True, resume=session_id)
      ) as client:
          await client.query("")  # Empty prompt to open the connection
          async for message in client.receive_response():
              await client.rewind_files(target.id)
              break
      print(f"Rewound to: {target.description}")

asyncio.run(main()) ```

```typescript TypeScript theme={null} import { query } from "@anthropic-ai/claude-agent-sdk";

// Store checkpoint metadata for better tracking interface Checkpoint { id: string; description: string; timestamp: Date; }

async function main() { const opts = { enableFileCheckpointing: true, permissionMode: "acceptEdits" as const, extraArgs: { "replay-user-messages": null } };

const response = query({
  prompt: "Refactor the authentication module",
  options: opts
});

const checkpoints: Checkpoint[] = [];
let sessionId: string | undefined;

for await (const message of response) {
  if (message.type === "user" && message.uuid) {
    checkpoints.push({
      id: message.uuid,
      description: `After turn ${checkpoints.length + 1}`,
      timestamp: new Date()
    });
  }
  if ("session_id" in message && !sessionId) {
    sessionId = message.session_id;
  }
}

// Later: rewind to any checkpoint by resuming the session
if (checkpoints.length > 0 && sessionId) {
  const target = checkpoints[0]; // Pick any checkpoint
  const rewindQuery = query({
    prompt: "", // Empty prompt to open the connection
    options: { ...opts, resume: sessionId }
  });

  for await (const msg of rewindQuery) {
    await rewindQuery.rewindFiles(target.id);
    break;
  }
  console.log(`Rewound to: ${target.description}`);
}

}

main(); ```

Try it out

This complete example creates a small utility file, has the agent add documentation comments, shows you the changes, then asks if you want to rewind.

Before you begin, make sure you have the Claude Agent SDK installed.

Create a new file called utils.py (Python) or utils.ts (TypeScript) and paste the following code:

<CodeGroup>
  ```python utils.py theme={null}
  def add(a, b):
      return a + b


  def subtract(a, b):
      return a - b


  def multiply(a, b):
      return a * b


  def divide(a, b):
      if b == 0:
          raise ValueError("Cannot divide by zero")
      return a / b
  ```

  ```typescript utils.ts theme={null}
  export function add(a: number, b: number): number {
    return a + b;
  }

  export function subtract(a: number, b: number): number {
    return a - b;
  }

  export function multiply(a: number, b: number): number {
    return a * b;
  }

  export function divide(a: number, b: number): number {
    if (b === 0) {
      throw new Error("Cannot divide by zero");
    }
    return a / b;
  }
  ```
</CodeGroup>

Create a new file called try_checkpointing.py (Python) or try_checkpointing.ts (TypeScript) in the same directory as your utility file, and paste the following code.

This script asks Claude to add doc comments to your utility file, then gives you the option to rewind and restore the original.

<CodeGroup>
  ```python try_checkpointing.py theme={null}
  import asyncio
  from claude_agent_sdk import (
      ClaudeSDKClient,
      ClaudeAgentOptions,
      UserMessage,
      ResultMessage,
  )


  async def main():
      # Configure the SDK with checkpointing enabled
      # - enable_file_checkpointing: Track file changes for rewinding
      # - permission_mode: Auto-accept file edits without prompting
      # - extra_args: Required to receive user message UUIDs in the stream
      options = ClaudeAgentOptions(
          enable_file_checkpointing=True,
          permission_mode="acceptEdits",
          extra_args={"replay-user-messages": None},
      )

      checkpoint_id = None  # Store the user message UUID for rewinding
      session_id = None  # Store the session ID for resuming

      print("Running agent to add doc comments to utils.py...\n")

      # Run the agent and capture checkpoint data from the response stream
      async with ClaudeSDKClient(options) as client:
          await client.query("Add doc comments to utils.py")

          async for message in client.receive_response():
              # Capture the first user message UUID - this is our restore point
              if isinstance(message, UserMessage) and message.uuid and not checkpoint_id:
                  checkpoint_id = message.uuid
              # Capture the session ID so we can resume later
              if isinstance(message, ResultMessage):
                  session_id = message.session_id

      print("Done! Open utils.py to see the added doc comments.\n")

      # Ask the user if they want to rewind the changes
      if checkpoint_id and session_id:
          response = input("Rewind to remove the doc comments? (y/n): ")

          if response.lower() == "y":
              # Resume the session with an empty prompt, then rewind
              async with ClaudeSDKClient(
                  ClaudeAgentOptions(enable_file_checkpointing=True, resume=session_id)
              ) as client:
                  await client.query("")  # Empty prompt opens the connection
                  async for message in client.receive_response():
                      await client.rewind_files(checkpoint_id)  # Restore files
                      break

              print(
                  "\n✓ File restored! Open utils.py to verify the doc comments are gone."
              )
          else:
              print("\nKept the modified file.")


  asyncio.run(main())
  ```

  ```typescript try_checkpointing.ts theme={null}
  import { query } from "@anthropic-ai/claude-agent-sdk";
  import * as readline from "readline";

  async function main() {
    // Configure the SDK with checkpointing enabled
    // - enableFileCheckpointing: Track file changes for rewinding
    // - permissionMode: Auto-accept file edits without prompting
    // - extraArgs: Required to receive user message UUIDs in the stream
    const opts = {
      enableFileCheckpointing: true,
      permissionMode: "acceptEdits" as const,
      extraArgs: { "replay-user-messages": null }
    };

    let sessionId: string | undefined; // Store the session ID for resuming
    let checkpointId: string | undefined; // Store the user message UUID for rewinding

    console.log("Running agent to add doc comments to utils.ts...\n");

    // Run the agent and capture checkpoint data from the response stream
    const response = query({
      prompt: "Add doc comments to utils.ts",
      options: opts
    });

    for await (const message of response) {
      // Capture the first user message UUID - this is our restore point
      if (message.type === "user" && message.uuid && !checkpointId) {
        checkpointId = message.uuid;
      }
      // Capture the session ID so we can resume later
      if ("session_id" in message) {
        sessionId = message.session_id;
      }
    }

    console.log("Done! Open utils.ts to see the added doc comments.\n");

    // Ask the user if they want to rewind the changes
    if (checkpointId && sessionId) {
      const rl = readline.createInterface({
        input: process.stdin,
        output: process.stdout
      });

      const answer = await new Promise<string>((resolve) => {
        rl.question("Rewind to remove the doc comments? (y/n): ", resolve);
      });
      rl.close();

      if (answer.toLowerCase() === "y") {
        // Resume the session with an empty prompt, then rewind
        const rewindQuery = query({
          prompt: "", // Empty prompt opens the connection
          options: { ...opts, resume: sessionId }
        });

        for await (const msg of rewindQuery) {
          await rewindQuery.rewindFiles(checkpointId); // Restore files
          break;
        }

        console.log("\n✓ File restored! Open utils.ts to verify the doc comments are gone.");
      } else {
        console.log("\nKept the modified file.");
      }
    }
  }

  main();
  ```
</CodeGroup>

This example demonstrates the complete checkpointing workflow:

1. **Enable checkpointing**: configure the SDK with `enable_file_checkpointing=True` and `permission_mode="acceptEdits"` to auto-approve file edits
2. **Capture checkpoint data**: as the agent runs, store the first user message UUID (your restore point) and the session ID
3. **Prompt for rewind**: after the agent finishes, check your utility file to see the doc comments, then decide if you want to undo the changes
4. **Resume and rewind**: if yes, resume the session with an empty prompt and call `rewind_files()` to restore the original file

Run the script from the same directory as your utility file.

<Tip>
  Open your utility file (`utils.py` or `utils.ts`) in your IDE or editor before running the script. You'll see the file update in real-time as the agent adds doc comments, then revert back to the original when you choose to rewind.
</Tip>

<Tabs>
  <Tab title="Python">
    ```bash theme={null}
    python try_checkpointing.py
    ```
  </Tab>

  <Tab title="TypeScript">
    ```bash theme={null}
    npx tsx try_checkpointing.ts
    ```
  </Tab>
</Tabs>

You'll see the agent add doc comments, then a prompt asking if you want to rewind. If you choose yes, the file is restored to its original state.

Limitations

File checkpointing has the following limitations:

Limitation Description
Write/Edit/NotebookEdit tools only Changes made through Bash commands are not tracked
Same session Checkpoints are tied to the session that created them
File content only Creating, moving, or deleting directories is not undone by rewinding
Local files Remote or network files are not tracked

Troubleshooting

Checkpointing options not recognized

If enableFileCheckpointing or rewindFiles() isn't available, you may be on an older SDK version.

Solution: Update to the latest SDK version:

User messages don't have UUIDs

If message.uuid is undefined or missing, you're not receiving checkpoint UUIDs.

Cause: The replay-user-messages option isn't set.

Solution: Add extra_args={"replay-user-messages": None} (Python) or extraArgs: { 'replay-user-messages': null } (TypeScript) to your options.

"No file checkpoint found for message" error

This error occurs when the checkpoint data doesn't exist for the specified user message UUID.

Common causes:

Solution: Ensure enable_file_checkpointing=True (Python) or enableFileCheckpointing: true (TypeScript) was set on the original session, then use the pattern shown in the examples: capture the first user message UUID, complete the session fully, then resume with an empty prompt and call rewindFiles() once.

"ProcessTransport is not ready for writing" error

This error occurs when you call rewindFiles() or rewind_files() after you've finished iterating through the response. The connection to the CLI process closes when the loop completes.

Solution: Resume the session with an empty prompt, then call rewind on the new query:

python Python theme={null} # Resume session with empty prompt, then rewind async with ClaudeSDKClient( ClaudeAgentOptions(enable_file_checkpointing=True, resume=session_id) ) as client: await client.query("") async for message in client.receive_response(): await client.rewind_files(checkpoint_id) break

```typescript TypeScript theme={null} // Resume session with empty prompt, then rewind const rewindQuery = query({ prompt: "", options: { ...opts, resume: sessionId } });

for await (const msg of rewindQuery) { await rewindQuery.rewindFiles(checkpointId); break; } ```

Next steps