# Python SDK Reference

> **Version Requirement**: This document is for CodeBuddy Agent SDK v0.1.0 and above.

This document provides a complete API reference for the Python SDK. For quick start and usage examples, please refer to [SDK Overview](sdk.md).

## Requirements

| Dependency | Version Requirement |
|---------|----------|
| Python | >= 3.10 |
| CodeBuddy CLI | Installed |

**Async Runtime**: The SDK is based on `asyncio`, all APIs are asynchronous.

## Installation

Recommended to use [uv](https://docs.astral.sh/uv/) for dependency management:

```bash
uv add codebuddy-agent-sdk
```

Or using pip:

```bash
pip install codebuddy-agent-sdk
```

### Environment Variables

| Variable Name | Description | Required |
|--------|------|------|
| `CODEBUDDY_CODE_PATH` | CodeBuddy CLI executable path | Optional |

If not set, the SDK will look for CLI in the following order:
1. Environment variable `CODEBUDDY_CODE_PATH`
2. Built-in binary within SDK package
3. Development environment monorepo path

### Authentication Configuration

The SDK supports authentication using existing login credentials, API Key, or OAuth Client Credentials. See [SDK Overview - Authentication Configuration](sdk.md#authentication-configuration) for details.

## Functions

### query()

Main API entry point, creates a query and returns an async iterator of messages.

```python
async def query(
    *,
    prompt: str | AsyncIterable[dict[str, Any]],
    options: CodeBuddyAgentOptions | None = None,
    transport: Transport | None = None,
) -> AsyncIterator[Message]:
```

**Parameters**:

| Parameter | Type | Description |
|------|------|------|
| `prompt` | `str \| AsyncIterable[dict]` | Query prompt or user message stream |
| `options` | `CodeBuddyAgentOptions` | Configuration options (optional) |
| `transport` | `Transport` | Custom transport layer (optional) |

**Returns**: `AsyncIterator[Message]` - Async iterator of messages

**Example**:

```python
from codebuddy_agent_sdk import query, AssistantMessage, TextBlock

async for message in query(prompt="What is 2+2?"):
    if isinstance(message, AssistantMessage):
        for block in message.content:
            if isinstance(block, TextBlock):
                print(block.text)
```

## Client Class

### CodeBuddySDKClient

Client class for bidirectional interactive conversations. Supports multi-turn dialogues, interruptions, and dynamic control.

```python
class CodeBuddySDKClient:
    def __init__(
        self,
        options: CodeBuddyAgentOptions | None = None,
        transport: Transport | None = None,
    ): ...
```

**Methods**:

#### connect()

Connect to CodeBuddy.

```python
async def connect(
    self,
    prompt: str | AsyncIterable[dict[str, Any]] | None = None
) -> None:
```

#### query()

Send user message.

```python
async def query(
    self,
    prompt: str | AsyncIterable[dict[str, Any]],
    session_id: str = "default",
) -> None:
```

#### receive_response()

Receive messages until a ResultMessage is received.

```python
async def receive_response(self) -> AsyncIterator[Message]:
```

#### receive_messages()

Receive all messages (does not auto-stop).

```python
async def receive_messages(self) -> AsyncIterator[Message]:
```

#### disconnect()

Disconnect.

```python
async def disconnect(self) -> None:
```

**Context Manager Support**:

```python
async with CodeBuddySDKClient() as client:
    await client.query("Hello!")
    async for msg in client.receive_response():
        print(msg)
```

#### mcp_server_status()

Get MCP server connection status.

```python
async def mcp_server_status(self) -> list[McpServerStatus]:
```

## Authentication

The SDK provides an independent authentication API with a **two-phase** design: first obtain the login URL, then wait for the user to complete authentication.

### authenticate()

Start the authentication flow, returns an `AuthFlow` object.

```python
async def authenticate(
    *,
    method_id: str = "external",
    environment: str | None = None,
    endpoint: str | None = None,
    codebuddy_code_path: str | None = None,
    env: dict[str, str] | None = None,
    timeout: float = 300.0,
) -> AuthFlow:
```

**Parameters**:

| Parameter | Type | Description |
|------|------|------|
| `method_id` | `str` | Authentication method identifier (default `"external"`) |
| `environment` | `str \| None` | Predefined environment name |
| `endpoint` | `str \| None` | Custom endpoint URL (mutually exclusive with environment) |
| `codebuddy_code_path` | `str \| None` | CLI executable path |
| `env` | `dict[str, str] \| None` | Additional environment variables |
| `timeout` | `float` | Timeout for user to complete login (seconds, default 300) |

**Returns**: `AuthFlow` — Awaitable object carrying the login URL

**Example**:

```python
from codebuddy_agent_sdk import authenticate

# Two-phase: get URL → show to user → wait for completion
auth = await authenticate()
if auth.auth_url:
    print(f"Please visit: {auth.auth_url}")
result = await auth
print(f"Welcome, {result.userinfo.user_name}")

# When already logged in, auth.auth_url is empty and await returns immediately
auth = await authenticate()
result = await auth  # Returns immediately if already logged in

# Custom timeout
auth = await authenticate()
result = await auth.wait(timeout=60)
```

### AuthFlow

Authentication flow object returned by `authenticate()`. Implements the `__await__` protocol and can be directly `await`ed.

**Attributes**:

| Attribute | Type | Description |
|------|------|------|
| `auth_url` | `str` | Login URL (empty string when already logged in) |
| `method_id` | `str \| None` | Authentication method identifier |

**Methods**:

#### wait()

Wait for the user to complete authentication.

```python
async def wait(self, timeout: float | None = None) -> AuthenticateResponse:
```

#### cancel()

Cancel the authentication flow and release resources.

```python
async def cancel(self) -> None:
```

### logout()

Log out and clear cached authentication tokens.

```python
async def logout(
    *,
    environment: str | None = None,
    endpoint: str | None = None,
    codebuddy_code_path: str | None = None,
    env: dict[str, str] | None = None,
) -> None:
```

**Example**:

```python
from codebuddy_agent_sdk import logout

await logout()
```

## Unstable API

> **Warning**: The following APIs are experimental and may change in future versions.

### interrupt()

Send interrupt signal.

```python
async def interrupt(self) -> None:
```

### set_permission_mode()

Dynamically modify permission mode.

```python
async def set_permission_mode(self, mode: str) -> None:
```

### set_model()

Dynamically modify model.

```python
async def set_model(self, model: str | None = None) -> None:
```

## Types

### CodeBuddyAgentOptions

Complete configuration options:

```python
@dataclass
class CodeBuddyAgentOptions:
    allowed_tools: list[str] = field(default_factory=list)
    disallowed_tools: list[str] = field(default_factory=list)
    system_prompt: str | AppendSystemPrompt | None = None
    mcp_servers: dict[str, McpServerConfig] | str | Path = field(default_factory=dict)
    permission_mode: PermissionMode | None = None
    continue_conversation: bool = False
    resume: str | None = None
    max_turns: int | None = None
    model: str | None = None
    fallback_model: str | None = None
    cwd: str | Path | None = None
    codebuddy_code_path: str | Path | None = None
    env: dict[str, str] = field(default_factory=dict)
    extra_args: dict[str, str | None] = field(default_factory=dict)
    stderr: Callable[[str], None] | None = None
    hooks: dict[HookEvent, list[HookMatcher]] | None = None
    include_partial_messages: bool = False
    fork_session: bool = False
    agents: dict[str, AgentDefinition] | None = None
    setting_sources: list[SettingSource] | None = None
    can_use_tool: CanUseTool | None = None
```

| Field | Type | Description |
|------|------|------|
| `allowed_tools` | `list[str]` | Tool whitelist to auto-allow |
| `disallowed_tools` | `list[str]` | Tool blacklist to disallow |
| `system_prompt` | `str \| AppendSystemPrompt` | System prompt configuration |
| `mcp_servers` | `dict[str, McpServerConfig]` | MCP server configuration |
| `permission_mode` | `PermissionMode` | Permission mode |
| `continue_conversation` | `bool` | Continue recent session |
| `resume` | `str` | Session ID to resume |
| `max_turns` | `int` | Maximum conversation turns |
| `model` | `str` | Specify model |
| `fallback_model` | `str` | Fallback model |
| `cwd` | `str \| Path` | Working directory |
| `codebuddy_code_path` | `str \| Path` | CLI executable path |
| `env` | `dict[str, str]` | Environment variables |
| `extra_args` | `dict[str, str \| None]` | Extra CLI arguments |
| `stderr` | `Callable[[str], None]` | stderr callback |
| `hooks` | `dict[HookEvent, list[HookMatcher]]` | Hook configuration |
| `include_partial_messages` | `bool` | Include partial messages |
| `fork_session` | `bool` | Fork session |
| `agents` | `dict[str, AgentDefinition]` | Custom agents |
| `setting_sources` | `list[SettingSource]` | Setting sources |
| `can_use_tool` | `CanUseTool` | Permission callback function |
| `max_thinking_tokens` | `int` | Maximum thinking tokens (deprecated, use `thinking` instead) |
| `thinking` | `ThinkingConfig` | Thinking mode configuration: `{"type": "adaptive"}`, `{"type": "enabled", "budget_tokens": N}`, or `{"type": "disabled"}` |
| `effort` | `'low' \| 'medium' \| 'high' \| 'xhigh'` | Model reasoning effort level |

### PermissionMode

```python
PermissionMode = Literal["default", "acceptEdits", "plan", "bypassPermissions"]
```

| Value | Description |
|-----|------|
| `"default"` | Default mode, all operations require confirmation |
| `"acceptEdits"` | Auto-approve file edits |
| `"plan"` | Planning mode, only allow reads |
| `"bypassPermissions"` | Skip all permission checks |

### PermissionResult

```python
PermissionResult = PermissionResultAllow | PermissionResultDeny

@dataclass
class PermissionResultAllow:
    updated_input: dict[str, Any]
    behavior: Literal["allow"] = "allow"
    updated_permissions: list[dict[str, Any]] | None = None

@dataclass
class PermissionResultDeny:
    message: str
    behavior: Literal["deny"] = "deny"
    interrupt: bool = False
```

### CanUseTool

```python
CanUseTool = Callable[
    [str, dict[str, Any], CanUseToolOptions],
    Awaitable[PermissionResult],
]

@dataclass
class CanUseToolOptions:
    tool_use_id: str
    signal: Any | None = None
    agent_id: str | None = None
    suggestions: list[dict[str, Any]] | None = None
    blocked_path: str | None = None
    decision_reason: str | None = None
```

### AgentDefinition

```python
@dataclass
class AgentDefinition:
    description: str        # Agent description
    prompt: str             # System prompt
    tools: list[str] | None = None           # Allowed tools
    disallowed_tools: list[str] | None = None  # Disallowed tools
    model: str | None = None                 # Model to use
```

### McpServerConfig

```python
class McpStdioServerConfig(TypedDict):
    type: NotRequired[Literal["stdio"]]
    command: str
    args: NotRequired[list[str]]
    env: NotRequired[dict[str, str]]

McpServerConfig = McpStdioServerConfig
```

### HookEvent

```python
HookEvent = (
    Literal["PreToolUse"]
    | Literal["PostToolUse"]
    | Literal["UserPromptSubmit"]
    | Literal["Stop"]
    | Literal["SubagentStop"]
    | Literal["PreCompact"]
    | Literal["WorktreeCreate"]
    | Literal["WorktreeRemove"]
)
```

### HookMatcher

```python
@dataclass
class HookMatcher:
    matcher: str | None = None      # Match pattern (supports regex)
    hooks: list[HookCallback] = field(default_factory=list)
    timeout: float | None = None    # Timeout in seconds
```

### HookCallback

```python
HookCallback = Callable[
    [Any, str | None, HookContext],
    Awaitable[HookJSONOutput],
]

class HookContext(TypedDict):
    signal: Any | None

class SyncHookJSONOutput(TypedDict):
    continue_: NotRequired[bool]
    suppressOutput: NotRequired[bool]
    stopReason: NotRequired[str]
    decision: NotRequired[Literal["block"]]
    reason: NotRequired[str]
```

### SettingSource

Controls which filesystem locations the SDK loads configuration from.

```python
SettingSource = Literal["user", "project", "local"]
```

| Value | Description | Location |
|-----|------|------|
| `"user"` | Global user settings | `~/.codebuddy/settings.json` |
| `"project"` | Project shared settings | `.codebuddy/settings.json` |
| `"local"` | Project local settings | `.codebuddy/settings.local.json` |

**Default Behavior**: When `setting_sources` is not specified, the SDK **does not load any filesystem configuration**. This provides a completely clean runtime environment.

```python
# Default: no configuration loaded (clean environment)
async for msg in query(prompt="..."):
    pass

# Load project configuration
options = CodeBuddyAgentOptions(setting_sources=["project"])

# Load all configurations (similar to CLI behavior)
options = CodeBuddyAgentOptions(setting_sources=["user", "project", "local"])
```

### AppendSystemPrompt

```python
@dataclass
class AppendSystemPrompt:
    append: str  # Content to append to default system prompt
```

## Message Types

### Message

Union of all message types:

```python
Message = UserMessage | AssistantMessage | SystemMessage | ResultMessage | StreamEvent
```

### SystemMessage

```python
@dataclass
class SystemMessage:
    subtype: str
    data: dict[str, Any]
```

### UserMessage

```python
@dataclass
class UserMessage:
    content: str | list[ContentBlock]
    uuid: str | None = None
    parent_tool_use_id: str | None = None
```

### AssistantMessage

```python
@dataclass
class AssistantMessage:
    content: list[ContentBlock]
    model: str
    parent_tool_use_id: str | None = None
    error: str | None = None
```

### ResultMessage

```python
@dataclass
class ResultMessage:
    subtype: str
    duration_ms: int
    duration_api_ms: int
    is_error: bool
    num_turns: int
    session_id: str
    total_cost_usd: float | None = None
    usage: dict[str, Any] | None = None
    result: str | None = None
```

### StreamEvent

```python
@dataclass
class StreamEvent:
    uuid: str
    session_id: str
    event: dict[str, Any]
    parent_tool_use_id: str | None = None
```

### ContentBlock

```python
ContentBlock = TextBlock | ThinkingBlock | ToolUseBlock | ToolResultBlock

@dataclass
class TextBlock:
    text: str

@dataclass
class ThinkingBlock:
    thinking: str
    signature: str

@dataclass
class ToolUseBlock:
    id: str
    name: str
    input: dict[str, Any]

@dataclass
class ToolResultBlock:
    tool_use_id: str
    content: str | list[dict[str, Any]] | None = None
    is_error: bool | None = None
```

## Input Types

### AskUserQuestionInput

```python
@dataclass
class AskUserQuestionInput:
    questions: list[AskUserQuestionQuestion]
    answers: dict[str, str] | None = None
```

### AskUserQuestionQuestion

```python
@dataclass
class AskUserQuestionQuestion:
    question: str     # Complete question text (should end with ?)
    header: str       # Short label (max 12 characters)
    options: list[AskUserQuestionOption]
    multi_select: bool  # Whether to allow multiple selections
```

### AskUserQuestionOption

```python
@dataclass
class AskUserQuestionOption:
    label: str        # Display text (1-5 words)
    description: str  # Option description
```

## Errors

All exceptions inherit from `CodeBuddySDKError`.

### CodeBuddySDKError

```python
class CodeBuddySDKError(Exception):
    """Base exception for CodeBuddy SDK errors."""
    pass
```

### CLIConnectionError

Thrown when connection to CLI fails or no connection is established.

```python
class CLIConnectionError(CodeBuddySDKError):
    pass
```

### CLINotFoundError

Thrown when CLI executable is not found.

```python
class CLINotFoundError(CodeBuddySDKError):
    def __init__(
        self,
        message: str,
        platform: str | None = None,
        arch: str | None = None,
    ): ...
```

**Attributes**:

| Attribute | Type | Description |
|------|------|------|
| `platform` | `str \| None` | Current platform |
| `arch` | `str \| None` | Current architecture |

### CLIJSONDecodeError

Thrown when JSON decoding of CLI output fails.

```python
class CLIJSONDecodeError(CodeBuddySDKError):
    pass
```

### ProcessError

Thrown when CLI process encounters an error.

```python
class ProcessError(CodeBuddySDKError):
    pass
```

### CLIStartupError

Thrown when the CLI process crashes or produces no output during the startup phase.

```python
class CLIStartupError(CodeBuddySDKError):
    def __init__(
        self,
        message: str,
        stderr: str = "",
        exit_code: int | None = None,
    ): ...
```

**Attributes**:

| Attribute | Type | Description |
|------|------|------|
| `stderr` | `str` | stderr output from CLI process |
| `exit_code` | `int \| None` | Process exit code |

### ExecutionError

Thrown when execution fails (e.g., authentication error, API error). Contains the errors array from ResultMessage.

```python
class ExecutionError(CodeBuddySDKError):
    def __init__(self, errors: list[str], subtype: str): ...
```

**Attributes**:

| Attribute | Type | Description |
|------|------|------|
| `errors` | `list[str]` | List of error messages |
| `subtype` | `str` | Error subtype |

### AuthenticationError

Thrown when authentication fails.

```python
class AuthenticationError(CodeBuddySDKError):
    def __init__(self, error_type: str, message: str): ...
```

**Attributes**:

| Attribute | Type | Description |
|------|------|------|
| `error_type` | `str` | Error type (e.g., `"timeout"`, `"auth_failed"`) |

## Auth Types

### AuthenticateResponse

```python
@dataclass(slots=True)
class AuthenticateResponse:
    userinfo: UserInfo
```

### UserInfo

```python
@dataclass(slots=True)
class UserInfo:
    user_id: str
    user_name: str = ""
    user_nickname: str = ""
    token: str = ""
    enterprise_id: str | None = None
    enterprise: str | None = None
```

### McpServerStatus

```python
@dataclass(slots=True)
class McpServerStatus:
    name: str
    status: Literal["connected", "failed", "needs-auth", "pending"]
    server_info: dict[str, Any] | None = None
```

## Related Documentation

- [SDK Overview](sdk.md) - Quick start and usage examples
- [TypeScript SDK Reference](sdk-typescript.md) - TypeScript version API
- [Hook Reference Guide](hooks.md) - Detailed Hook configuration instructions
- [MCP Integration](mcp.md) - MCP server configuration guide
