* fix: strip stale mcp-session-id header to prevent 'Session not found' error loop
When VSCode reconnects to LiteLLM's MCP endpoint after a reload, it sends
a stale mcp-session-id header. The session was already cleaned up, causing
a 404 'Session not found' error. VSCode retries with the same stale ID,
creating an infinite error loop.
Before forwarding requests to the StreamableHTTP session manager, check if
the mcp-session-id header references a valid session. If the session doesn't
exist, strip the header so a new session is created automatically.
Fixes#20292
* refactor: extract stale session handling into _strip_stale_mcp_session_header helper
* Fix PLR0915: Extract system message handling to reduce statement count
* fix mypy
* fix: add host_progress_callback parameter to mock_call_tool in test
The test_call_tool_without_broken_pipe_error was failing because the mock function did not accept the host_progress_callback keyword argument that the actual implementation passes to client.call_tool(). Updated the mock to accept this parameter to match the real implementation signature.
* fixing flaky tests around oidc and email
* Add documentation comment to test file
* add retry
* add dependency
* increase retry
---------
Co-authored-by: yuneng-jiang <yuneng.jiang@gmail.com>
Forward static_headers from /mcp-rest/test/* routes into the MCP client so headers are present during session.initialize() and tool discovery.
Also add a shared merge_mcp_headers() helper to keep header precedence consistent and ensure OpenAPI-to-MCP generated tools include static_headers.
Tests:
- pytest tests/test_litellm/proxy/_experimental/mcp_server/test_rest_endpoints.py
- pytest tests/test_litellm/proxy/_experimental/mcp_server/test_mcp_server_manager.py -k register_openapi_tools_includes_static_headers
Fixes#19341
Co-authored-by: Krish Dholakia <krrishdholakia@gmail.com>
- Keep **kwargs approach (no exec()) for security
- Integrate path traversal validation from main branch
- Add URL encoding for path parameters
- Merge both test suites (edge cases + security tests)
- All 14 tests passing
- Add to_safe_identifier() to convert any parameter name to valid Python identifier
- Refactor create_tool_function() to use closure with **kwargs instead of exec()
- Handle edge cases: hyphens, dots, leading digits, Python keywords, special chars
- Add comprehensive test suite covering all edge cases
- Fixes#18471: OpenAPI MCP server crashes on invalid parameter names
- Security: Eliminates arbitrary code execution risk from untrusted OpenAPI specs
* feat(mcp): preserve tool metadata and full CallToolResult in MCP gateway
This PR fixes two issues that prevented ChatGPT from rendering MCP UI widgets
when proxied through LiteLLM:
1. Preserve Tool Metadata in tools/list
- Modified _create_prefixed_tools() to mutate tools in place instead of
reconstructing them, preserving all fields including metadata/_meta
- This ensures ChatGPT can see 'openai/outputTemplate' URIs in tools/list
and will call resources/read to fetch widgets
2. Preserve Full CallToolResult (structuredContent + metadata)
- Changed call_mcp_tool() and _handle_managed_mcp_tool() to return full
CallToolResult objects instead of just content
- Updated error handlers to return CallToolResult with isError flag
- Wrapped local tool results in CallToolResult objects
- This preserves structuredContent and metadata fields needed for widget rendering
Files changed:
- litellm/proxy/_experimental/mcp_server/mcp_server_manager.py
- litellm/proxy/_experimental/mcp_server/server.py
Fixes issues where ChatGPT could not render MCP UI widgets when using
LiteLLM as an MCP gateway.
* feat(mcp): Preserve tool metadata and return full CallToolResult for ChatGPT UI widgets
- Preserve metadata and _meta fields when creating prefixed tools
- Return full CallToolResult instead of just content list
- Ensures ChatGPT can discover and render UI widgets via openai/outputTemplate
- Fixes metadata stripping that prevented widget rendering in ChatGPT
Changes:
- mcp_server_manager.py: Mutate tools in place to preserve all fields including metadata
- server.py: Return CallToolResult with structuredContent and metadata preserved
- Added test to verify metadata preservation
* fix: guard cost calculator when BaseModel lacks _hidden_params
---------
Co-authored-by: Afroz Ahmad <aahmad@Afrozs-MacBook-Pro.local>
Co-authored-by: Afroz Ahmad <aahmad@KNDMCPTMZH3.sephoraus.com>
Sameer Kankute