Title: feat: propagate session_id from transport to tool context by cbcoutinho · Pull Request #1608 · modelcontextprotocol/python-sdk · GitHub
Open Graph Title: feat: propagate session_id from transport to tool context by cbcoutinho · Pull Request #1608 · modelcontextprotocol/python-sdk
X Title: feat: propagate session_id from transport to tool context by cbcoutinho · Pull Request #1608 · modelcontextprotocol/python-sdk
Description: Summary This PR enables tools to access the transport-level session ID via Context.session_id, supporting session-level tracing and observability use cases. Changes InitializationOptions: Add optional session_id field ServerSession: Store and expose session_id via property RequestContext: Add session_id field to dataclass StreamableHTTPSessionManager: Pass session_id when creating initialization options FastMCP Context: Add session_id property accessible in tools Tests: Comprehensive test suite for session_id propagation Usage Tools can now access the session ID like this: @mcp.tool() async def my_tool(ctx: Context) -> dict: session_id = ctx.session_id # Transport's session ID (streamable-http) # Use for tracing, logging, correlation, etc. return {"session_id": session_id} Behavior Streamable-HTTP (stateful): ctx.session_id returns the transport's session ID (UUID) Streamable-HTTP (stateless): ctx.session_id returns None (no session tracking) stdio/SSE transports: ctx.session_id returns None (session_id not set during initialization) Use Cases Distributed Tracing: Add session_id as a span attribute in OpenTelemetry traces to correlate all tool calls within a session Session Analytics: Track per-session metrics and usage patterns Debugging: Correlate logs and errors across multiple requests in the same session Audit Trails: Associate all operations with a session identifier Testing All 418 existing server tests pass ✓ New test suite covers session_id propagation scenarios Verified no regressions in FastMCP, auth, resource tests Fixes #485 #942 Related Related to #421 (OpenTelemetry tracing integration) Breaking Changes None. This is a backward-compatible addition: New optional field in InitializationOptions New property on Context (returns None if not available) Existing code continues to work without modifications
Open Graph Description: Summary This PR enables tools to access the transport-level session ID via Context.session_id, supporting session-level tracing and observability use cases. Changes InitializationOptions: Add opti...
X Description: Summary This PR enables tools to access the transport-level session ID via Context.session_id, supporting session-level tracing and observability use cases. Changes InitializationOptions: Add opti...
Opengraph URL: https://github.com/modelcontextprotocol/python-sdk/pull/1608
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