- Move mcp from optional to required dependencies
- Remove all conditional imports and HAS_MCP checks
- Clean, simple imports at module level
- SDK MCP servers are a core feature, not optional
This is cleaner and simpler - if you install claude-code-sdk,
you get full MCP support out of the box.
- MCP is an optional dependency for the SDK
- But if you use SDK MCP servers, you must have it installed
- Import at runtime in the method that needs it
- Clear ImportError if MCP not installed when using MCP features
- Replace MCP SDK type imports with simpler duck-typing approach
- Use getattr to access server handlers without importing MCP types
- Add sdk_mcp_servers extraction in ClaudeSDKClient
- This avoids import errors when mcp package isn't installed
## Summary
This PR implements control protocol support in the Python SDK, aligning
it with the TypeScript implementation pattern. The refactor introduces a
Query + Transport separation to enable bidirectional communication
between the SDK and CLI.
## Motivation
The previous Python SDK implementation used a high-level abstraction in
the Transport ABC (`send_request`/`receive_messages`) that couldn't
handle bidirectional communication. This prevented support for:
- Control messages from CLI to SDK that need responses
- Hooks implementation
- Dynamic permission mode changes
- SDK MCP servers
## Changes
### Core Architecture Refactor
1. **New Query Class** (`src/claude_code_sdk/_internal/query.py`)
- Manages control protocol on top of Transport
- Handles control request/response routing
- Manages initialization handshake with timeout
- Supports hook callbacks and tool permission callbacks
- Implements message streaming
2. **Refactored Transport ABC**
(`src/claude_code_sdk/_internal/transport/__init__.py`)
- Changed from high-level (`send_request`/`receive_messages`) to
low-level (`write`/`read_messages`) interface
- Now handles raw I/O instead of protocol logic
- Aligns with TypeScript ProcessTransport pattern
3. **Updated SubprocessCLITransport**
(`src/claude_code_sdk/_internal/transport/subprocess_cli.py`)
- Simplified to focus on raw message streaming
- Removed protocol logic (moved to Query)
- Improved cleanup and error handling
4. **Enhanced ClaudeSDKClient** (`src/claude_code_sdk/client.py`)
- Now uses Query for control protocol
- Supports initialization messages
- Better error handling for control protocol failures
### Control Protocol Features
- **Initialization handshake**: SDK sends initialize request, CLI
responds with supported commands
- **Control message types**:
- `initialize`: Establish bidirectional connection
- `interrupt`: Cancel ongoing operations
- `set_permission_mode`: Change permission mode dynamically
- **Timeout handling**: 60-second timeout for initialization to handle
CLI versions without control support
### Examples
Updated `examples/streaming_mode.py` to demonstrate control protocol
initialization and error handling.
## Testing
- Tested with current CLI (no control protocol support yet) - gracefully
falls back
- Verified backward compatibility with existing `query()` function
- Tested initialization timeout handling
- Verified proper cleanup on errors
## Design Alignment
This implementation closely follows the TypeScript reference:
- `src/core/Query.ts` → `src/claude_code_sdk/_internal/query.py`
- `src/transport/ProcessTransport.ts` →
`src/claude_code_sdk/_internal/transport/subprocess_cli.py`
- `src/entrypoints/sdk.ts` → `src/claude_code_sdk/client.py`
## Next Steps
Once the CLI implements the control protocol handler, this will enable:
- Hooks support
- Dynamic permission mode changes
- SDK MCP servers
- Improved error recovery
🤖 Generated with [Claude Code](https://claude.ai/code)
---------
Co-authored-by: Ashwin Bhat <ashwin@anthropic.com>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Kashyap Murali <kashyap@anthropic.com>
- Update test_transport.py: disconnect() -> close(), is_connected() -> is_ready()
- Update test_subprocess_buffering.py: receive_messages() -> read_messages()
- Fix test_streaming_client.py edge cases:
- Add control protocol init to test_double_connect (use side_effect for multiple mocks)
- Add control protocol init to test_receive_response_list_comprehension
- Add control protocol init to test_concurrent_send_receive
- All transport method calls now use read_messages() instead of receive_messages()
Test results: 89 of 90 tests passing (1 subprocess test still needs work)
- Update test mocks to handle control protocol initialization
- Fix interrupt test to check for control requests via write() instead of interrupt()
- Add control protocol support to mock_receive functions in streaming tests
- Ensure all tests properly handle init handshake before sending messages
- Fix formatting issues (trailing whitespace, blank lines)
All tests now properly support the new Query/Transport architecture with
bidirectional control protocol communication.
- Applied ruff formatting to all files
- Integrated async/sync fixes from dickson/control branch
- Fixed import conflicts between TYPE_CHECKING and contextlib
- All SDK MCP tests passing
- Move json import to top-level imports
- Add asyncio and contextlib.suppress imports for future use
- Remove inline json import from query method
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
- Rebased SDK MCP implementation onto PR #139's control protocol refactoring
- Moved SDK MCP handling from Transport to Query class for proper layering
- Transport now only filters SDK servers from CLI config
- Query class handles SDK MCP control requests via _handle_sdk_mcp_request
- Added tool decorator and create_sdk_mcp_server API functions
- Added McpSdkServerConfig type definition
- Updated documentation with SDK MCP examples
- Added integration tests for SDK MCP functionality
This implementation properly layers SDK MCP on top of the bidirectional control protocol from PR #139, ensuring clean separation between transport (I/O) and query (protocol) layers.
The subprocess transport was ignoring user-specified cwd from
ClaudeCodeOptions, causing the working directory preference to be
overridden by os.environ. This fix ensures the CWD environment variable
is properly passed to child processes.
- Add PWD env var when self._cwd is set in SubprocessCLITransport
- Fixes issue where custom working directory was not respected
- Maintains backward compatibility
Tests: All existing tests pass
The PR should address the issue where user prompt maybe treated as a
option with leading `-`
Assuming `claude` does follow POSIX standard, the `--` option should
solve the issue.
fixes#129
This PR simplifies the example with interrupt.
There is a flag interrupt_sent that isn't required since the execution
loop will terminate after interrupt with the following message:
`{"content": [{"type": "text", "text": "[Request interrupted by
user]"}]}`
## Key changes
- Adds env field to `ClaudeCodeOptions`, allowing custom env vars to cli
- Updates tests and examples
## Motivation
Bringing Python SDK to feature parity with TS SDK, which supports custom
env vars
## Notes
- Environment variables are merged in order: system env → user env → SDK
required vars
- This implementation seems slightly more robust than the TypeScript
version, which can exclude OS envs vars if a user passes a minimal env
object
- Some linting changes seem to have been picked up
## Summary
This PR exposes the `Transport` interface in the public API, enabling
users to pass custom transport implementations to the `query()`
function. Previously, transport selection was internal and users had no
way to provide custom implementations.
**Primary Benefits:**
- 🔌 **Remote claude code** - Connect to Claude Code CLIs running
remotely
- The concrete use case here is to be able to implement a custom
transport that can communicate to claude code instances running in
remote sandboxes. Currently the the sdk only works with Claude Codes
running in a local subprocess limiting the scenarios in which this SDK
can be used.
## Changes
### Public API Changes
- **Exposed the previously internal `Transport` abstract base class** in
`claude_code_sdk.__init__.py`
- **Added `transport` parameter** to `query()` function signature
- **Updated docstring** with transport parameter documentation
### Internal Changes
- **Modified `InternalClient.process_query()`** to accept optional
transport parameter
- **Added transport selection logic** - use provided transport or
default to `SubprocessCLITransport`
- **Updated `__all__` exports** to include `Transport`
### Testing
- **Updated existing tests** to work with new transport parameter
- **Maintained backward compatibility** - all existing code continues to
work unchanged
## Testing
### Existing Tests
- ✅ All existing unit tests pass with new transport parameter
- ✅ Integration tests updated to mock new transport interface
- ✅ Subprocess buffering tests continue to work with exposed transport
### New Functionality Testing
- ✅ Verified custom transport can be passed to `query()`
- ✅ Confirmed default behavior unchanged when no transport provided
- ✅ Validated transport lifecycle ( connect → receive → disconnect)
- ✅ Tested transport interface compliance with abstract base class
## Example Usage
### Basic Custom Transport
```python
from claude_code_sdk import query, ClaudeCodeOptions, Transport
class MyCustomTransport(Transport):
# Implement abstract methods: connect, disconnect,
# send_request, receive_messages, is_connected
pass
transport = MyCustomTransport()
async for message in query(
prompt="Hello",
transport=transport
):
print(message)
```
## Related
- #85🤖 Generated with [Claude Code](https://claude.ai/code)
---------
Signed-off-by: Rushil Patel <rpatel@codegen.com>
This PR updates the version to 0.0.20 after publishing to PyPI.
## Changes
- Updated version in `pyproject.toml`
- Updated version in `src/claude_code_sdk/__init__.py`
## Release Information
- Published to PyPI: https://pypi.org/project/claude-code-sdk/0.0.20/
- Install with: `pip install claude-code-sdk==0.0.20`
🤖 Generated by GitHub Actions
---------
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
## Summary
Fixes an issue where `thinking` content blocks in Claude Code responses
were not being parsed, resulting in empty `AssistantMessage` content
arrays.
## Changes
- Added `ThinkingBlock` dataclass to handle thinking content with
`thinking` and `signature` fields
- Updated client parsing logic in `_internal/client.py` to recognize and
create `ThinkingBlock` instances
- Added comprehensive test coverage for thinking block functionality
## Before
```python
# Claude Code response with thinking block resulted in:
AssistantMessage(content=[]) # Empty content!
```
## After
```python
# Now correctly parses to:
AssistantMessage(content=[
ThinkingBlock(thinking="...", signature="...")
])
```
Fixes#27
---------
Co-authored-by: Dickson Tsai <dickson@anthropic.com>
`claude`'s `--mcp-config` takes either a JSON file or string, so support
this in `ClaudeCodeOptions`
```
--mcp-config <file or string> Load MCP servers from a JSON file or string
```
---------
Co-authored-by: claude[bot] <209825114+claude[bot]@users.noreply.github.com>
Co-authored-by: Sam Fu <shunfu@users.noreply.github.com>
## Summary
- Adds `extra_args` field to `ClaudeCodeOptions` to support passing
arbitrary CLI flags
- Enables forward compatibility with future CLI flags without requiring
SDK updates
- Supports both valued flags (`--flag value`) and boolean flags
(`--flag`)
## Changes
- Add `extra_args: dict[str, str | None]` field to `ClaudeCodeOptions`
- Implement logic in `SubprocessCLITransport` to handle extra args:
- `None` values create boolean flags (e.g., `{"verbose": None}` →
`--verbose`)
- String values create flags with arguments (e.g., `{"output": "json"}`
→ `--output json`)
- Add comprehensive tests for the new functionality
## Test plan
- [x] Added unit tests for settings file path handling
- [x] Added unit tests for settings JSON object handling
- [x] Added unit tests for extra_args with both valued and boolean flags
- [x] All tests pass (`python -m pytest tests/`)
- [x] Type checking passes (`python -m mypy src/`)
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-authored-by: Claude <noreply@anthropic.com>
the `mcp_tools` field in `ClaudeCodeOptions` seems to have been there
since the initial commit but I couldn't find any references in the repo,
so I believe it may be vestigial and unused
This PR updates the version to 0.0.19 after publishing to PyPI.
## Changes
- Updated version in `pyproject.toml`
- Updated version in `src/claude_code_sdk/__init__.py`
## Release Information
- Published to PyPI: https://pypi.org/project/claude-code-sdk/0.0.19/
- Install with: `pip install claude-code-sdk==0.0.19`
🤖 Generated by GitHub Actions
---------
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
## Summary
Fixes a critical deadlock issue that occurs when MCP servers produce
verbose stderr output. The SDK would hang indefinitely when the stderr
pipe buffer filled up.
## The Problem
The deadlock occurred due to sequential reading of subprocess streams:
1. SDK reads stdout completely before reading stderr
2. When stderr pipe buffer fills (64KB on Linux, 16KB on macOS),
subprocess blocks on write
3. Subprocess can't continue to stdout, parent waits for stdout →
**DEADLOCK** 🔒
## The Solution
Redirect stderr to a temporary file instead of a pipe:
- **No pipe buffer** = no possibility of deadlock
- Temp file can grow as needed (no 64KB limit)
- Still capture stderr for error reporting (last 100 lines)
- Works consistently across all async backends
## Implementation Details
- `stderr=tempfile.NamedTemporaryFile()` instead of `stderr=PIPE`
- Use `deque(maxlen=100)` to keep only recent stderr lines in memory
- Temp file is automatically cleaned up on disconnect
- Add `[stderr truncated, showing last 100 lines]` message when buffer
is full
## Testing
- Verified no deadlock with 150+ lines of stderr output
- Confirmed stderr is still captured for error reporting
- All existing tests pass
- Works with asyncio, trio, and other anyio backends
## Impact
- Fixes consistent hangs in production with MCP servers
- No functional regression - stderr handling is preserved
- Simpler than concurrent reading alternatives
- More robust than pipe-based solutions
Fixes the issue reported in Slack where SDK would hang indefinitely when
receiving messages from MCP servers with verbose logging.
🤖 Generated with [Claude Code](https://claude.ai/code)
---------
Co-authored-by: Claude <noreply@anthropic.com>
This PR updates the version to 0.0.18 after publishing to PyPI.
## Changes
- Updated version in `pyproject.toml`
- Updated version in `src/claude_code_sdk/__init__.py`
## Release Information
- Published to PyPI: https://pypi.org/project/claude-code-sdk/0.0.18/
- Install with: `pip install claude-code-sdk==0.0.18`
🤖 Generated by GitHub Actions
---------
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
## Summary
- Add `settings` field to `ClaudeCodeOptions` to expose the `--settings`
CLI flag
- Allow SDK users to specify custom settings configuration path
## Changes
- Added `settings: str | None = None` field to `ClaudeCodeOptions`
dataclass
- Added CLI argument conversion logic in `SubprocessCLITransport` to
pass `--settings` flag to Claude Code CLI
## Test plan
- [x] All existing tests pass
- [x] Linting passes (`python -m ruff check`)
- [x] Type checking passes (`python -m mypy src/`)
🤖 Generated with [Claude Code](https://claude.ai/code)
---------
Co-authored-by: Claude <noreply@anthropic.com>
This PR updates the version to 0.0.17 after publishing to PyPI.
## Changes
- Updated version in `pyproject.toml`
- Updated version in `src/claude_code_sdk/__init__.py`
## Release Information
- Published to PyPI: https://pypi.org/project/claude-code-sdk/0.0.17/
- Install with: `pip install claude-code-sdk==0.0.17`
🤖 Generated by GitHub Actions
---------
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