Skill 寫法圖鑑

claude-agent-sdk-python

WalterSumbon | Agent 與工作流 | 原文 | Apache-2.0

用 Python 搭配 Claude Agent SDK 建構 AI agent 的指南

中文翻譯

---
name: claude-agent-sdk-python
description: >
  用 Python 搭配 Claude Agent SDK 建構 AI agent 的專家指引。
  當使用者用 Python 寫 SDK 程式碼、import claude_agent_sdk、使用 query()、
  ClaudeSDKClient、ClaudeAgentOptions、AgentDefinition、建立自訂的 @tool 函式、
  設定 hook、整合 MCP server、管理 session,或是在 Python 裡除錯 SDK 問題時使用。
  也會在這些字串出現時觸發:"claude_agent_sdk"、"ClaudeAgentOptions"、"from claude_agent_sdk import"、
  "pip install claude-agent-sdk"、"asyncio.run",或是 "async for message in query"。
---

# Claude Agent SDK — Python Guide

用 Python 搭配 Claude Agent SDK 建構 AI agent 的 production 級指引。

> **命名**:Claude Code SDK 已改名為 Claude Agent SDK(v0.1.0 起)。
> 套件:`pip install claude-agent-sdk` · Import:`from claude_agent_sdk import ...`

## Message Types

所有訊息類型,供型別檢查和 `isinstance()` 檢查使用:

```python
from claude_agent_sdk import (
    AssistantMessage,     # Claude 的文字/工具回應
    ResultMessage,        # 最終結果,帶有 subtype(success/error/cancelled)
    SystemMessage,        # 系統事件(session_id 等)
    UserMessage,          # 使用者的 prompt
    ToolUseMessage,       # 工具呼叫請求
    ToolResultMessage,    # 工具執行結果
)
```

## Quick Reference — Two Interaction Modes

### 1. `query()` — Stateless, One-Shot

最適合:獨立任務、自動化 script、CI pipeline。

```python
import asyncio
from claude_agent_sdk import query, ClaudeAgentOptions, AssistantMessage, ResultMessage

async def main():
    async for message in query(
        prompt="Review utils.py for bugs. Fix any issues you find.",
        options=ClaudeAgentOptions(
            allowed_tools=["Read", "Edit", "Glob"],
            permission_mode="acceptEdits",
        ),
    ):
        if isinstance(message, AssistantMessage):
            for block in message.content:
                if hasattr(block, "text"):
                    print(block.text)
                elif hasattr(block, "name"):
                    print(f"Tool: {block.name}")
        elif isinstance(message, ResultMessage):
            print(f"Done: {message.subtype}")

asyncio.run(main())
```

### 2. `ClaudeSDKClient` — Stateful, Multi-Turn

最適合:對話、追問、互動式應用。

```python
from claude_agent_sdk import ClaudeSDKClient, ClaudeAgentOptions

async with ClaudeSDKClient(
    options=ClaudeAgentOptions(
        allowed_tools=["Read", "Write", "Bash"],
        permission_mode="acceptEdits",
    )
) as client:
    await client.query("Analyze the codebase structure")
    async for msg in client.receive_messages():
        print(msg)
    # 保留 context 繼續對話
    await client.query("Now refactor the largest file you found")
    async for msg in client.receive_messages():
        print(msg)
```

## ClaudeAgentOptions — Complete Configuration

所有選項都是選填。主要欄位:

| 欄位 | 型別 | 說明 |
|-------|------|-------------|
| `allowed_tools` | `list[str] \| None` | Claude 可以使用的工具。見下方 Built-in Tools。 |
| `disallowed_tools` | `list[str] \| None` | 明確封鎖特定工具。 |
| `permission_mode` | `"default" \| "acceptEdits" \| "bypassPermissions"` | 權限策略。 |
| `system_prompt` | `str \| dict \| None` | 自訂指示。要用 CC 預設的話,用 `{"type": "preset", "preset": "claude_code"}`。 |
| `model` | `str \| None` | 例如 `"sonnet"`、`"opus"`、`"haiku"`,或完整的 model 字串。 |
| `cwd` | `str \| Path \| None` | agent 的工作目錄。 |
| `max_turns` | `int \| None` | agentic 迴圈的最大迭代次數。 |
| `setting_sources` | `list[Literal["user", "project"]] \| None` | 用 `["user", "project"]` 從檔案系統載入 Skills/CLAUDE.md。 |
| `mcp_servers` | `dict \| None` | MCP server 設定。 |
| `agents` | `dict[str, AgentDefinition] \| None` | 具名的 subagent 定義。 |
| `hooks` | `dict \| None` | 生命週期 hook 的 callback。 |

### Built-in Tools

給 `allowed_tools` 用的工具名稱:

- **檔案操作**:`Read`、`Write`、`Edit`、`MultiEdit`
- **搜尋**:`Glob`、`Grep`
- **執行**:`Bash`
- **網路**:`WebSearch`、`WebFetch`
- **委派**:`Task`(subagent 必要)
- **Skills**:`Skill`(需要 `setting_sources`)

## Custom Tools via SDK MCP Server

不需要另外的 MCP server 行程,就能定義行程內(in-process)的工具:

```python
from claude_agent_sdk import tool, create_sdk_mcp_server, ClaudeAgentOptions

@tool("search_orders", "Search orders by customer ID", {"customer_id": str, "status": str})
async def search_orders(args):
    results = await db.query_orders(args["customer_id"], args.get("status"))
    return {"content": [{"type": "text", "text": json.dumps(results)}]}

@tool("send_email", "Send an email notification", {"to": str, "subject": str, "body": str})
async def send_email(args):
    await email_service.send(args["to"], args["subject"], args["body"])
    return {"content": [{"type": "text", "text": f"Email sent to {args['to']}"}]}

server = create_sdk_mcp_server(name="business-tools", tools=[search_orders, send_email])

options = ClaudeAgentOptions(
    mcp_servers={"biz": server},
    allowed_tools=["mcp__biz__search_orders", "mcp__biz__send_email"],
)
```

**工具命名慣例**:MCP 工具的存取名稱是 `mcp__<server-name>__<tool-name>`。

## Subagents

把專門的任務委派給隔離的 agent,它們有自己的 context 和工具權限:

```python
from claude_agent_sdk import query, ClaudeAgentOptions, AgentDefinition

async for message in query(
    prompt="Review auth module for security issues, then write tests",
    options=ClaudeAgentOptions(
        allowed_tools=["Read", "Grep", "Glob", "Task"],  # Task 是必要的
        agents={
            "security-reviewer": AgentDefinition(
                description="Security specialist. Use for vulnerability analysis.",
                prompt="You are a security expert. Analyze code for OWASP Top 10...",
                tools=["Read", "Grep", "Glob"],
                model="opus",
            ),
            "test-writer": AgentDefinition(
                description="Test specialist. Use to generate test suites.",
                prompt="You are a testing expert. Write comprehensive unit tests...",
                tools=["Read", "Write", "Bash"],
                model="sonnet",
            ),
        },
    ),
):
    print(message)
```

動態產生 agent 的 **Factory 模式**:

```python
def create_reviewer(language: str) -> AgentDefinition:
    return AgentDefinition(
        description=f"{language} code review specialist",
        prompt=f"You are an expert {language} developer...",
        tools=["Read", "Grep", "Glob"],
        model="opus" if language in ["rust", "c++"] else "sonnet",
    )
```

## Hooks — Lifecycle Callbacks

可用的事件:`PreToolUse`、`PostToolUse`、`Stop`、`SessionStart`、`SessionEnd`、`UserPromptSubmit`。

```python
from claude_agent_sdk import query, ClaudeAgentOptions, HookMatcher

async def block_dangerous_commands(input_data, tool_use_id, context):
    """Block destructive bash commands."""
    if input_data.get("tool_name") == "Bash":
        cmd = input_data.get("tool_input", {}).get("command", "")
        if any(danger in cmd for danger in ["rm -rf /", "DROP TABLE", "mkfs"]):
            return {
                "hookSpecificOutput": {
                    "hookEventName": "PreToolUse",
                    "permissionDecision": "deny",
                    "permissionDecisionReason": f"Blocked dangerous command: {cmd}",
                }
            }
    return {}

async def audit_log(input_data, tool_use_id, context):
    """Log all tool usage for auditing."""
    with open("audit.log", "a") as f:
        f.write(f"{input_data.get('tool_name')}: {input_data.get('tool_input')}\n")
    return {}

options = ClaudeAgentOptions(
    hooks={
        "PreToolUse": [
            HookMatcher(matcher="Bash", hooks=[block_dangerous_commands]),
            HookMatcher(matcher=".*", hooks=[audit_log]),
        ]
    }
)
```

## MCP Integration (External Servers)

```python
options = ClaudeAgentOptions(
    mcp_servers={
        "github": {
            "type": "stdio",
            "command": "npx",
            "args": ["-y", "@modelcontextprotocol/server-github"],
            "env": {"GITHUB_TOKEN": os.getenv("GITHUB_TOKEN")},
        },
        "postgres": {
            "type": "stdio",
            "command": "docker",
            "args": ["run", "mcp-postgres-server"],
            "env": {"DATABASE_URL": os.getenv("DATABASE_URL")},
        },
    },
    allowed_tools=["mcp__github", "mcp__postgres"],
)
```

同一份設定裡可以混用 SDK MCP server(行程內)和外部 MCP server。

## Using Skills in the SDK

Skills 是以檔案系統為基礎,必須明確啟用:

```python
options = ClaudeAgentOptions(
    cwd="/path/to/project",
    setting_sources=["user", "project"],  # 必要:從檔案系統載入 Skills
    allowed_tools=["Skill", "Read", "Write", "Bash"],
)
```

**常見錯誤**:忘了 `setting_sources`。沒有它,就算 `allowed_tools` 裡有 `"Skill"`,Skills 也不會被發現。

Skill 的位置:
- **Project**:`.claude/skills/*/SKILL.md`(透過 git 共用)
- **User**:`~/.claude/skills/*/SKILL.md`(個人的,跨專案)

注意:SKILL.md frontmatter 裡的 `allowed-tools` 欄位**只在 Claude Code CLI 有效**,在 SDK 裡無效。要控制工具存取,請用 `ClaudeAgentOptions` 裡的 `allowed_tools`。

## Sessions and Conversation Management

```python
from claude_agent_sdk import query, ClaudeAgentOptions

session_id = None

# 第一次互動:抓取 session_id
async for message in query(
    prompt="Review this codebase and identify the top 3 issues",
    options=ClaudeAgentOptions(allowed_tools=["Read", "Glob", "Grep"]),
):
    if message.type == "system" and hasattr(message, "session_id"):
        session_id = message.session_id
    print(message)

# 帶著 context 接續
async for message in query(
    prompt="Now fix issue #1 that you found",
    options=ClaudeAgentOptions(
        session_id=session_id,
        allowed_tools=["Read", "Edit", "Bash"],
        permission_mode="acceptEdits",
    ),
):
    print(message)
```

## System Prompt Configuration

```python
# 1. 自訂 system prompt(v0.1.0+ 的預設:精簡 prompt)
options = ClaudeAgentOptions(system_prompt="You are a senior Python engineer...")

# 2. Claude Code 完整的 system prompt(需要主動選用)
options = ClaudeAgentOptions(
    system_prompt={"type": "preset", "preset": "claude_code"}
)

# 3. 沒有 system prompt:SDK 預設(精簡)
options = ClaudeAgentOptions()  # 使用內建的精簡 prompt
```

**v0.1.0 的破壞性變更**:SDK 預設不再載入 Claude Code 的 system prompt。如果你需要舊的行為,要明確設定 `preset: "claude_code"`。

## Authentication

```bash
# Direct API (default)
export ANTHROPIC_API_KEY=your-api-key

# Amazon Bedrock
export CLAUDE_CODE_USE_BEDROCK=1
# + configure AWS credentials

# Google Vertex AI
export CLAUDE_CODE_USE_VERTEX=1
# + configure GCP credentials

# Microsoft Azure AI Foundry
export CLAUDE_CODE_USE_FOUNDRY=1
# + configure Azure credentials
```

## Common Patterns

### Batch Processing (Parallel Agents)

```python
import asyncio

async def process_file(filepath: str):
    async for msg in query(
        prompt=f"Review {filepath} for security issues",
        options=ClaudeAgentOptions(
            allowed_tools=["Read", "Grep"],
            max_turns=50,
        ),
    ):
        if isinstance(msg, ResultMessage):
            return msg.result

results = await asyncio.gather(
    process_file("auth.py"),
    process_file("payments.py"),
    process_file("users.py"),
)
```

### Structured Output Collection

```python
messages = []
async for msg in query(prompt="Analyze this codebase", options=options):
    messages.append(msg)

# 擷取最終結果
result = next((m for m in reversed(messages) if hasattr(m, "result")), None)
```

### Error Handling

可用的例外類型:
- `CLINotFoundError`:在 PATH 裡找不到 Claude Code CLI 執行檔
- `CLIConnectionError`:無法連接到 CLI 行程
- 也可能拋出標準的 Python 例外(例如 `asyncio.TimeoutError`)

```python
from claude_agent_sdk import CLINotFoundError, CLIConnectionError

try:
    async for msg in query(prompt="...", options=options):
        print(msg)
except CLINotFoundError:
    print("Claude Code CLI not found. Install: curl -fsSL https://claude.ai/install.sh | bash")
except CLIConnectionError as e:
    print(f"Connection error: {e}")
```

## Migration from Claude Code SDK (< v0.1.0)

主要變更:
1. `ClaudeCodeOptions` → `ClaudeAgentOptions`
2. System prompt 預設不再載入 Claude Code 的 prompt
3. `setting_sources` 必須明確設定(以前是自動載入)
4. Import 路徑不變(`claude_agent_sdk`),但類別名稱變了

## Best Practices

1. **最小權限原則**:只給 agent 真正需要的工具。
2. **自動化用 `permission_mode="acceptEdits"`**,互動使用用 `"default"`。
3. **自訂工具優先用 SDK MCP server**,不要用外部的:開銷較小,也比較好除錯。
4. **專門的任務用 subagent**:隔離 context,並依任務套用合適的 model。
5. **加 hook 來確保安全**:在 production 封鎖危險指令並稽核工具使用。
6. **設定 `max_turns`**,防止 agent 在 production 環境失控。
7. **用 `cwd`** 把 agent 限定在特定目錄。
8. **從 system 訊息抓取 `session_id`**,如果你需要對話的連續性。

> 常見問題的排解,見 `references/troubleshooting.md`。

## Official Resources

- Overview: https://platform.claude.com/docs/en/agent-sdk/overview
- Quickstart: https://platform.claude.com/docs/en/agent-sdk/quickstart
- Python reference: https://platform.claude.com/docs/en/agent-sdk/python
- Migration guide: https://platform.claude.com/docs/en/agent-sdk/migration-guide
- Python SDK repo: https://github.com/anthropics/claude-agent-sdk-python
- Demo agents: https://github.com/anthropics/claude-agent-sdk-demos
- Cookbook: https://platform.claude.com/cookbook

英文原文

---
name: claude-agent-sdk-python
description: >
  Expert guidance for building AI agents with the Claude Agent SDK in Python.
  Use when the user writes Python code with the SDK, imports claude_agent_sdk, uses query(),
  ClaudeSDKClient, ClaudeAgentOptions, AgentDefinition, creates custom @tool functions,
  sets up hooks, integrates MCP servers, manages sessions, or debugs SDK issues in Python.
  Also triggers on: "claude_agent_sdk", "ClaudeAgentOptions", "from claude_agent_sdk import",
  "pip install claude-agent-sdk", "asyncio.run", or "async for message in query".
---

# Claude Agent SDK — Python Guide

Production guidance for building AI agents with the Claude Agent SDK in Python.

> **Naming**: The Claude Code SDK was renamed to the Claude Agent SDK (v0.1.0+).
> Package: `pip install claude-agent-sdk` · Import: `from claude_agent_sdk import ...`

## Message Types

All message types for type checking and `isinstance()` checks:

```python
from claude_agent_sdk import (
    AssistantMessage,     # Claude's text/tool responses
    ResultMessage,        # Final result with subtype (success/error/cancelled)
    SystemMessage,        # System events (session_id, etc.)
    UserMessage,          # User prompts
    ToolUseMessage,       # Tool invocation requests
    ToolResultMessage,    # Tool execution results
)
```

## Quick Reference — Two Interaction Modes

### 1. `query()` — Stateless, One-Shot

Best for: independent tasks, automation scripts, CI pipelines.

```python
import asyncio
from claude_agent_sdk import query, ClaudeAgentOptions, AssistantMessage, ResultMessage

async def main():
    async for message in query(
        prompt="Review utils.py for bugs. Fix any issues you find.",
        options=ClaudeAgentOptions(
            allowed_tools=["Read", "Edit", "Glob"],
            permission_mode="acceptEdits",
        ),
    ):
        if isinstance(message, AssistantMessage):
            for block in message.content:
                if hasattr(block, "text"):
                    print(block.text)
                elif hasattr(block, "name"):
                    print(f"Tool: {block.name}")
        elif isinstance(message, ResultMessage):
            print(f"Done: {message.subtype}")

asyncio.run(main())
```

### 2. `ClaudeSDKClient` — Stateful, Multi-Turn

Best for: conversations, follow-up questions, interactive apps.

```python
from claude_agent_sdk import ClaudeSDKClient, ClaudeAgentOptions

async with ClaudeSDKClient(
    options=ClaudeAgentOptions(
        allowed_tools=["Read", "Write", "Bash"],
        permission_mode="acceptEdits",
    )
) as client:
    await client.query("Analyze the codebase structure")
    async for msg in client.receive_messages():
        print(msg)
    # Continue the conversation with context preserved
    await client.query("Now refactor the largest file you found")
    async for msg in client.receive_messages():
        print(msg)
```

## ClaudeAgentOptions — Complete Configuration

All options are optional. Key fields:

| Field | Type | Description |
|-------|------|-------------|
| `allowed_tools` | `list[str] \| None` | Tools Claude can use. See Built-in Tools below. |
| `disallowed_tools` | `list[str] \| None` | Explicitly block specific tools. |
| `permission_mode` | `"default" \| "acceptEdits" \| "bypassPermissions"` | Permission strategy. |
| `system_prompt` | `str \| dict \| None` | Custom instructions. Use `{"type": "preset", "preset": "claude_code"}` for CC default. |
| `model` | `str \| None` | e.g. `"sonnet"`, `"opus"`, `"haiku"`, or full model string. |
| `cwd` | `str \| Path \| None` | Working directory for the agent. |
| `max_turns` | `int \| None` | Maximum agentic loop iterations. |
| `setting_sources` | `list[Literal["user", "project"]] \| None` | `["user", "project"]` to load Skills/CLAUDE.md from filesystem. |
| `mcp_servers` | `dict \| None` | MCP server configurations. |
| `agents` | `dict[str, AgentDefinition] \| None` | Named subagent definitions. |
| `hooks` | `dict \| None` | Lifecycle hook callbacks. |

### Built-in Tools

Tool names for `allowed_tools`:

- **File ops**: `Read`, `Write`, `Edit`, `MultiEdit`
- **Search**: `Glob`, `Grep`
- **Execution**: `Bash`
- **Web**: `WebSearch`, `WebFetch`
- **Delegation**: `Task` (required for subagents)
- **Skills**: `Skill` (requires `setting_sources`)

## Custom Tools via SDK MCP Server

Define in-process tools without a separate MCP server process:

```python
from claude_agent_sdk import tool, create_sdk_mcp_server, ClaudeAgentOptions

@tool("search_orders", "Search orders by customer ID", {"customer_id": str, "status": str})
async def search_orders(args):
    results = await db.query_orders(args["customer_id"], args.get("status"))
    return {"content": [{"type": "text", "text": json.dumps(results)}]}

@tool("send_email", "Send an email notification", {"to": str, "subject": str, "body": str})
async def send_email(args):
    await email_service.send(args["to"], args["subject"], args["body"])
    return {"content": [{"type": "text", "text": f"Email sent to {args['to']}"}]}

server = create_sdk_mcp_server(name="business-tools", tools=[search_orders, send_email])

options = ClaudeAgentOptions(
    mcp_servers={"biz": server},
    allowed_tools=["mcp__biz__search_orders", "mcp__biz__send_email"],
)
```

**Tool naming convention**: MCP tools are accessed as `mcp__<server-name>__<tool-name>`.

## Subagents

Delegate specialized tasks to isolated agents with their own context and tool permissions:

```python
from claude_agent_sdk import query, ClaudeAgentOptions, AgentDefinition

async for message in query(
    prompt="Review auth module for security issues, then write tests",
    options=ClaudeAgentOptions(
        allowed_tools=["Read", "Grep", "Glob", "Task"],  # Task is required
        agents={
            "security-reviewer": AgentDefinition(
                description="Security specialist. Use for vulnerability analysis.",
                prompt="You are a security expert. Analyze code for OWASP Top 10...",
                tools=["Read", "Grep", "Glob"],
                model="opus",
            ),
            "test-writer": AgentDefinition(
                description="Test specialist. Use to generate test suites.",
                prompt="You are a testing expert. Write comprehensive unit tests...",
                tools=["Read", "Write", "Bash"],
                model="sonnet",
            ),
        },
    ),
):
    print(message)
```

**Factory pattern** for dynamic agents:

```python
def create_reviewer(language: str) -> AgentDefinition:
    return AgentDefinition(
        description=f"{language} code review specialist",
        prompt=f"You are an expert {language} developer...",
        tools=["Read", "Grep", "Glob"],
        model="opus" if language in ["rust", "c++"] else "sonnet",
    )
```

## Hooks — Lifecycle Callbacks

Available events: `PreToolUse`, `PostToolUse`, `Stop`, `SessionStart`, `SessionEnd`, `UserPromptSubmit`.

```python
from claude_agent_sdk import query, ClaudeAgentOptions, HookMatcher

async def block_dangerous_commands(input_data, tool_use_id, context):
    """Block destructive bash commands."""
    if input_data.get("tool_name") == "Bash":
        cmd = input_data.get("tool_input", {}).get("command", "")
        if any(danger in cmd for danger in ["rm -rf /", "DROP TABLE", "mkfs"]):
            return {
                "hookSpecificOutput": {
                    "hookEventName": "PreToolUse",
                    "permissionDecision": "deny",
                    "permissionDecisionReason": f"Blocked dangerous command: {cmd}",
                }
            }
    return {}

async def audit_log(input_data, tool_use_id, context):
    """Log all tool usage for auditing."""
    with open("audit.log", "a") as f:
        f.write(f"{input_data.get('tool_name')}: {input_data.get('tool_input')}\n")
    return {}

options = ClaudeAgentOptions(
    hooks={
        "PreToolUse": [
            HookMatcher(matcher="Bash", hooks=[block_dangerous_commands]),
            HookMatcher(matcher=".*", hooks=[audit_log]),
        ]
    }
)
```

## MCP Integration (External Servers)

```python
options = ClaudeAgentOptions(
    mcp_servers={
        "github": {
            "type": "stdio",
            "command": "npx",
            "args": ["-y", "@modelcontextprotocol/server-github"],
            "env": {"GITHUB_TOKEN": os.getenv("GITHUB_TOKEN")},
        },
        "postgres": {
            "type": "stdio",
            "command": "docker",
            "args": ["run", "mcp-postgres-server"],
            "env": {"DATABASE_URL": os.getenv("DATABASE_URL")},
        },
    },
    allowed_tools=["mcp__github", "mcp__postgres"],
)
```

You can mix SDK MCP servers (in-process) and external MCP servers in the same config.

## Using Skills in the SDK

Skills are filesystem-based and must be explicitly enabled:

```python
options = ClaudeAgentOptions(
    cwd="/path/to/project",
    setting_sources=["user", "project"],  # REQUIRED — loads Skills from filesystem
    allowed_tools=["Skill", "Read", "Write", "Bash"],
)
```

**Common mistake**: forgetting `setting_sources`. Without it, Skills won't be discovered even if `"Skill"` is in `allowed_tools`.

Skill locations:
- **Project**: `.claude/skills/*/SKILL.md` (shared via git)
- **User**: `~/.claude/skills/*/SKILL.md` (personal, cross-project)

Note: The `allowed-tools` field in SKILL.md frontmatter **only works in Claude Code CLI**, not in the SDK. Use `allowed_tools` in `ClaudeAgentOptions` to control tool access.

## Sessions and Conversation Management

```python
from claude_agent_sdk import query, ClaudeAgentOptions

session_id = None

# First interaction — capture session_id
async for message in query(
    prompt="Review this codebase and identify the top 3 issues",
    options=ClaudeAgentOptions(allowed_tools=["Read", "Glob", "Grep"]),
):
    if message.type == "system" and hasattr(message, "session_id"):
        session_id = message.session_id
    print(message)

# Resume with context
async for message in query(
    prompt="Now fix issue #1 that you found",
    options=ClaudeAgentOptions(
        session_id=session_id,
        allowed_tools=["Read", "Edit", "Bash"],
        permission_mode="acceptEdits",
    ),
):
    print(message)
```

## System Prompt Configuration

```python
# 1. Custom system prompt (v0.1.0+ default: minimal prompt)
options = ClaudeAgentOptions(system_prompt="You are a senior Python engineer...")

# 2. Claude Code's full system prompt (opt-in)
options = ClaudeAgentOptions(
    system_prompt={"type": "preset", "preset": "claude_code"}
)

# 3. No system prompt — SDK default (minimal)
options = ClaudeAgentOptions()  # uses minimal built-in prompt
```

**Breaking change in v0.1.0**: The SDK no longer loads Claude Code's system prompt by default. If you need the old behavior, explicitly set `preset: "claude_code"`.

## Authentication

```bash
# Direct API (default)
export ANTHROPIC_API_KEY=your-api-key

# Amazon Bedrock
export CLAUDE_CODE_USE_BEDROCK=1
# + configure AWS credentials

# Google Vertex AI
export CLAUDE_CODE_USE_VERTEX=1
# + configure GCP credentials

# Microsoft Azure AI Foundry
export CLAUDE_CODE_USE_FOUNDRY=1
# + configure Azure credentials
```

## Common Patterns

### Batch Processing (Parallel Agents)

```python
import asyncio

async def process_file(filepath: str):
    async for msg in query(
        prompt=f"Review {filepath} for security issues",
        options=ClaudeAgentOptions(
            allowed_tools=["Read", "Grep"],
            max_turns=50,
        ),
    ):
        if isinstance(msg, ResultMessage):
            return msg.result

results = await asyncio.gather(
    process_file("auth.py"),
    process_file("payments.py"),
    process_file("users.py"),
)
```

### Structured Output Collection

```python
messages = []
async for msg in query(prompt="Analyze this codebase", options=options):
    messages.append(msg)

# Extract final result
result = next((m for m in reversed(messages) if hasattr(m, "result")), None)
```

### Error Handling

Available exception types:
- `CLINotFoundError` — Claude Code CLI binary not found in PATH
- `CLIConnectionError` — Failed to connect to CLI process
- Standard Python exceptions (e.g., `asyncio.TimeoutError`) may also be raised

```python
from claude_agent_sdk import CLINotFoundError, CLIConnectionError

try:
    async for msg in query(prompt="...", options=options):
        print(msg)
except CLINotFoundError:
    print("Claude Code CLI not found. Install: curl -fsSL https://claude.ai/install.sh | bash")
except CLIConnectionError as e:
    print(f"Connection error: {e}")
```

## Migration from Claude Code SDK (< v0.1.0)

Key changes:
1. `ClaudeCodeOptions` → `ClaudeAgentOptions`
2. System prompt no longer loads Claude Code's prompt by default
3. `setting_sources` must be explicitly set (was auto-loaded before)
4. Import path unchanged (`claude_agent_sdk`), but class names changed

## Best Practices

1. **Principle of least privilege**: Only grant tools the agent actually needs.
2. **Use `permission_mode="acceptEdits"` for automation**, `"default"` for interactive use.
3. **Prefer SDK MCP servers** over external ones for custom tools — less overhead, easier debugging.
4. **Use subagents for specialized tasks** — isolate context and apply the right model per task.
5. **Add hooks for safety** — block dangerous commands and audit tool usage in production.
6. **Set `max_turns`** to prevent runaway agents in production environments.
7. **Use `cwd`** to scope the agent to a specific directory.
8. **Capture `session_id`** from system messages if you need conversation continuity.

> For troubleshooting common issues, see `references/troubleshooting.md`.

## Official Resources

- Overview: https://platform.claude.com/docs/en/agent-sdk/overview
- Quickstart: https://platform.claude.com/docs/en/agent-sdk/quickstart
- Python reference: https://platform.claude.com/docs/en/agent-sdk/python
- Migration guide: https://platform.claude.com/docs/en/agent-sdk/migration-guide
- Python SDK repo: https://github.com/anthropics/claude-agent-sdk-python
- Demo agents: https://github.com/anthropics/claude-agent-sdk-demos
- Cookbook: https://platform.claude.com/cookbook