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Agent SDK overview

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Documentation Index

Fetch the complete documentation index at: https://code.claude.com/docs/llms.txt Use this file to discover all available pages before exploring further.

Agent SDK overview

Build production AI agents with Claude Code as a library

The Claude Code SDK has been renamed to the Claude Agent SDK. If you're migrating from the old SDK, see the Migration Guide.

Build AI agents that autonomously read files, run commands, search the web, edit code, and more. The Agent SDK gives you the same tools, agent loop, and context management that power Claude Code, programmable in Python and TypeScript.

Opus 4.7 (claude-opus-4-7) requires Agent SDK v0.2.111 or later. If you see a thinking.type.enabled API error, see Troubleshooting.

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

async def main(): async for message in query( prompt="Find and fix the bug in auth.py", options=ClaudeAgentOptions(allowed_tools=["Read", "Edit", "Bash"]), ): print(message) # Claude reads the file, finds the bug, edits it

asyncio.run(main()) ```

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

for await (const message of query({ prompt: "Find and fix the bug in auth.ts", options: { allowedTools: ["Read", "Edit", "Bash"] } })) { console.log(message); // Claude reads the file, finds the bug, edits it } ```

The Agent SDK includes built-in tools for reading files, running commands, and editing code, so your agent can start working immediately without you implementing tool execution. Dive into the quickstart or explore real agents built with the SDK:

Build a bug-fixing agent in minutes

Email assistant, research agent, and more

Get started

bash theme={null} npm install @anthropic-ai/claude-agent-sdk 

  <Tab title="Python">
    ```bash theme={null}
    pip install claude-agent-sdk
    ```
  </Tab>
</Tabs>

<Note>
  The TypeScript SDK bundles a native Claude Code binary for your platform as an optional dependency, so you don't need to install Claude Code separately.
</Note>

Get an API key from the Console, then set it as an environment variable:

```bash theme={null}
export ANTHROPIC_API_KEY=your-api-key
```

The SDK also supports authentication via third-party API providers:

* **Amazon Bedrock**: set `CLAUDE_CODE_USE_BEDROCK=1` environment variable and configure AWS credentials
* **Google Vertex AI**: set `CLAUDE_CODE_USE_VERTEX=1` environment variable and configure Google Cloud credentials
* **Microsoft Azure**: set `CLAUDE_CODE_USE_FOUNDRY=1` environment variable and configure Azure credentials

See the setup guides for [Bedrock](https://code.claude.com/en/amazon-bedrock), [Vertex AI](https://code.claude.com/en/google-vertex-ai), or [Azure AI Foundry](https://code.claude.com/en/microsoft-foundry) for details.

<Note>
  Unless previously approved, Anthropic does not allow third party developers to offer claude.ai login or rate limits for their products, including agents built on the Claude Agent SDK. Please use the API key authentication methods described in this document instead.
</Note>

This example creates an agent that lists files in your current directory using built-in tools.

<CodeGroup>
  ```python Python theme={null}
  import asyncio
  from claude_agent_sdk import query, ClaudeAgentOptions


  async def main():
      async for message in query(
          prompt="What files are in this directory?",
          options=ClaudeAgentOptions(allowed_tools=["Bash", "Glob"]),
      ):
          if hasattr(message, "result"):
              print(message.result)


  asyncio.run(main())
  ```

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

  for await (const message of query({
    prompt: "What files are in this directory?",
    options: { allowedTools: ["Bash", "Glob"] }
  })) {
    if ("result" in message) console.log(message.result);
  }
  ```
</CodeGroup>

Ready to build? Follow the Quickstart to create an agent that finds and fixes bugs in minutes.

Capabilities

Everything that makes Claude Code powerful is available in the SDK:

Your agent can read files, run commands, and search codebases out of the box. Key tools include:

| Tool                                                                        | What it does                                                        |
| --------------------------------------------------------------------------- | ------------------------------------------------------------------- |
| **Read**                                                                    | Read any file in the working directory                              |
| **Write**                                                                   | Create new files                                                    |
| **Edit**                                                                    | Make precise edits to existing files                                |
| **Bash**                                                                    | Run terminal commands, scripts, git operations                      |
| **Monitor**                                                                 | Watch a background script and react to each output line as an event |
| **Glob**                                                                    | Find files by pattern (`**/*.ts`, `src/**/*.py`)                    |
| **Grep**                                                                    | Search file contents with regex                                     |
| **WebSearch**                                                               | Search the web for current information                              |
| **WebFetch**                                                                | Fetch and parse web page content                                    |
| **[AskUserQuestion](https://code.claude.com/en/agent-sdk/user-input#handle-clarifying-questions)** | Ask the user clarifying questions with multiple choice options      |

This example creates an agent that searches your codebase for TODO comments:

<CodeGroup>
  ```python Python theme={null}
  import asyncio
  from claude_agent_sdk import query, ClaudeAgentOptions


  async def main():
      async for message in query(
          prompt="Find all TODO comments and create a summary",
          options=ClaudeAgentOptions(allowed_tools=["Read", "Glob", "Grep"]),
      ):
          if hasattr(message, "result"):
              print(message.result)


  asyncio.run(main())
  ```

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

  for await (const message of query({
    prompt: "Find all TODO comments and create a summary",
    options: { allowedTools: ["Read", "Glob", "Grep"] }
  })) {
    if ("result" in message) console.log(message.result);
  }
  ```
</CodeGroup>

Run custom code at key points in the agent lifecycle. SDK hooks use callback functions to validate, log, block, or transform agent behavior.

**Available hooks:** `PreToolUse`, `PostToolUse`, `Stop`, `SessionStart`, `SessionEnd`, `UserPromptSubmit`, and more.

This example logs all file changes to an audit file:

<CodeGroup>
  ```python Python theme={null}
  import asyncio
  from datetime import datetime
  from claude_agent_sdk import query, ClaudeAgentOptions, HookMatcher


  async def log_file_change(input_data, tool_use_id, context):
      file_path = input_data.get("tool_input", {}).get("file_path", "unknown")
      with open("./audit.log", "a") as f:
          f.write(f"{datetime.now()}: modified {file_path}\n")
      return {}


  async def main():
      async for message in query(
          prompt="Refactor utils.py to improve readability",
          options=ClaudeAgentOptions(
              permission_mode="acceptEdits",
              hooks={
                  "PostToolUse": [
                      HookMatcher(matcher="Edit|Write", hooks=[log_file_change])
                  ]
              },
          ),
      ):
          if hasattr(message, "result"):
              print(message.result)


  asyncio.run(main())
  ```

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

  const logFileChange: HookCallback = async (input) => {
    const filePath = (input as any).tool_input?.file_path ?? "unknown";
    await appendFile("./audit.log", `${new Date().toISOString()}: modified ${filePath}\n`);
    return {};
  };

  for await (const message of query({
    prompt: "Refactor utils.py to improve readability",
    options: {
      permissionMode: "acceptEdits",
      hooks: {
        PostToolUse: [{ matcher: "Edit|Write", hooks: [logFileChange] }]
      }
    }
  })) {
    if ("result" in message) console.log(message.result);
  }
  ```
</CodeGroup>

[Learn more about hooks →](https://code.claude.com/en/agent-sdk/hooks)

Spawn specialized agents to handle focused subtasks. Your main agent delegates work, and subagents report back with results.

Define custom agents with specialized instructions. Include `Agent` in `allowedTools` since subagents are invoked via the Agent tool:

<CodeGroup>
  ```python Python theme={null}
  import asyncio
  from claude_agent_sdk import query, ClaudeAgentOptions, AgentDefinition


  async def main():
      async for message in query(
          prompt="Use the code-reviewer agent to review this codebase",
          options=ClaudeAgentOptions(
              allowed_tools=["Read", "Glob", "Grep", "Agent"],
              agents={
                  "code-reviewer": AgentDefinition(
                      description="Expert code reviewer for quality and security reviews.",
                      prompt="Analyze code quality and suggest improvements.",
                      tools=["Read", "Glob", "Grep"],
                  )
              },
          ),
      ):
          if hasattr(message, "result"):
              print(message.result)


  asyncio.run(main())
  ```

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

  for await (const message of query({
    prompt: "Use the code-reviewer agent to review this codebase",
    options: {
      allowedTools: ["Read", "Glob", "Grep", "Agent"],
      agents: {
        "code-reviewer": {
          description: "Expert code reviewer for quality and security reviews.",
          prompt: "Analyze code quality and suggest improvements.",
          tools: ["Read", "Glob", "Grep"]
        }
      }
    }
  })) {
    if ("result" in message) console.log(message.result);
  }
  ```
</CodeGroup>

Messages from within a subagent's context include a `parent_tool_use_id` field, letting you track which messages belong to which subagent execution.

[Learn more about subagents →](https://code.claude.com/en/agent-sdk/subagents)

Connect to external systems via the Model Context Protocol: databases, browsers, APIs, and hundreds more.

This example connects the [Playwright MCP server](https://github.com/microsoft/playwright-mcp) to give your agent browser automation capabilities:

<CodeGroup>
  ```python Python theme={null}
  import asyncio
  from claude_agent_sdk import query, ClaudeAgentOptions


  async def main():
      async for message in query(
          prompt="Open example.com and describe what you see",
          options=ClaudeAgentOptions(
              mcp_servers={
                  "playwright": {"command": "npx", "args": ["@playwright/mcp@latest"]}
              }
          ),
      ):
          if hasattr(message, "result"):
              print(message.result)


  asyncio.run(main())
  ```

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

  for await (const message of query({
    prompt: "Open example.com and describe what you see",
    options: {
      mcpServers: {
        playwright: { command: "npx", args: ["@playwright/mcp@latest"] }
      }
    }
  })) {
    if ("result" in message) console.log(message.result);
  }
  ```
</CodeGroup>

[Learn more about MCP →](https://code.claude.com/en/agent-sdk/mcp)

Control exactly which tools your agent can use. Allow safe operations, block dangerous ones, or require approval for sensitive actions.

<Note>
  For interactive approval prompts and the `AskUserQuestion` tool, see [Handle approvals and user input](https://code.claude.com/en/agent-sdk/user-input).
</Note>

This example creates a read-only agent that can analyze but not modify code. `allowed_tools` pre-approves `Read`, `Glob`, and `Grep`.

<CodeGroup>
  ```python Python theme={null}
  import asyncio
  from claude_agent_sdk import query, ClaudeAgentOptions


  async def main():
      async for message in query(
          prompt="Review this code for best practices",
          options=ClaudeAgentOptions(
              allowed_tools=["Read", "Glob", "Grep"],
          ),
      ):
          if hasattr(message, "result"):
              print(message.result)


  asyncio.run(main())
  ```

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

  for await (const message of query({
    prompt: "Review this code for best practices",
    options: {
      allowedTools: ["Read", "Glob", "Grep"]
    }
  })) {
    if ("result" in message) console.log(message.result);
  }
  ```
</CodeGroup>

[Learn more about permissions →](https://code.claude.com/en/agent-sdk/permissions)

Maintain context across multiple exchanges. Claude remembers files read, analysis done, and conversation history. Resume sessions later, or fork them to explore different approaches.

This example captures the session ID from the first query, then resumes to continue with full context:

<CodeGroup>
  ```python Python theme={null}
  import asyncio
  from claude_agent_sdk import query, ClaudeAgentOptions, SystemMessage, ResultMessage


  async def main():
      session_id = None

      # First query: capture the session ID
      async for message in query(
          prompt="Read the authentication module",
          options=ClaudeAgentOptions(allowed_tools=["Read", "Glob"]),
      ):
          if isinstance(message, SystemMessage) and message.subtype == "init":
              session_id = message.data["session_id"]

      # Resume with full context from the first query
      async for message in query(
          prompt="Now find all places that call it",  # "it" = auth module
          options=ClaudeAgentOptions(resume=session_id),
      ):
          if isinstance(message, ResultMessage):
              print(message.result)


  asyncio.run(main())
  ```

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

  let sessionId: string | undefined;

  // First query: capture the session ID
  for await (const message of query({
    prompt: "Read the authentication module",
    options: { allowedTools: ["Read", "Glob"] }
  })) {
    if (message.type === "system" && message.subtype === "init") {
      sessionId = message.session_id;
    }
  }

  // Resume with full context from the first query
  for await (const message of query({
    prompt: "Now find all places that call it", // "it" = auth module
    options: { resume: sessionId }
  })) {
    if ("result" in message) console.log(message.result);
  }
  ```
</CodeGroup>

[Learn more about sessions →](https://code.claude.com/en/agent-sdk/sessions)

Claude Code features

The SDK also supports Claude Code's filesystem-based configuration. With default options the SDK loads these from .claude/ in your working directory and ~/.claude/. To restrict which sources load, set setting_sources (Python) or settingSources (TypeScript) in your options.

Feature Description Location
Skills Specialized capabilities defined in Markdown .claude/skills/*/SKILL.md
Slash commands Custom commands for common tasks .claude/commands/*.md
Memory Project context and instructions CLAUDE.md or .claude/CLAUDE.md
Plugins Extend with custom commands, agents, and MCP servers Programmatic via plugins option

Compare the Agent SDK to other Claude tools

The Claude Platform offers multiple ways to build with Claude. Here's how the Agent SDK fits in:

The Anthropic Client SDK gives you direct API access: you send prompts and implement tool execution yourself. The Agent SDK gives you Claude with built-in tool execution.

With the Client SDK, you implement a tool loop. With the Agent SDK, Claude handles it:

<CodeGroup>
  ```python Python theme={null}
  # Client SDK: You implement the tool loop
  response = client.messages.create(...)
  while response.stop_reason == "tool_use":
      result = your_tool_executor(response.tool_use)
      response = client.messages.create(tool_result=result, **params)

  # Agent SDK: Claude handles tools autonomously
  async for message in query(prompt="Fix the bug in auth.py"):
      print(message)
  ```

  ```typescript TypeScript theme={null}
  // Client SDK: You implement the tool loop
  let response = await client.messages.create({ ...params });
  while (response.stop_reason === "tool_use") {
    const result = yourToolExecutor(response.tool_use);
    response = await client.messages.create({ tool_result: result, ...params });
  }

  // Agent SDK: Claude handles tools autonomously
  for await (const message of query({ prompt: "Fix the bug in auth.ts" })) {
    console.log(message);
  }
  ```
</CodeGroup>

Same capabilities, different interface:

| Use case                | Best choice |
| ----------------------- | ----------- |
| Interactive development | CLI         |
| CI/CD pipelines         | SDK         |
| Custom applications     | SDK         |
| One-off tasks           | CLI         |
| Production automation   | SDK         |

Many teams use both: CLI for daily development, SDK for production. Workflows translate directly between them.

Changelog

View the full changelog for SDK updates, bug fixes, and new features:

Reporting bugs

If you encounter bugs or issues with the Agent SDK:

Branding guidelines

For partners integrating the Claude Agent SDK, use of Claude branding is optional. When referencing Claude in your product:

Allowed:

Not permitted:

Your product should maintain its own branding and not appear to be Claude Code or any Anthropic product. For questions about branding compliance, contact the Anthropic sales team.

License and terms

Use of the Claude Agent SDK is governed by Anthropic's Commercial Terms of Service, including when you use it to power products and services that you make available to your own customers and end users, except to the extent a specific component or dependency is covered by a different license as indicated in that component's LICENSE file.

Next steps

Build an agent that finds and fixes bugs in minutes

Email assistant, research agent, and more

Full TypeScript API reference and examples

Full Python API reference and examples