Remove unused StreamableHTTPTransport.get_session_id()
Removes the dead StreamableHTTPTransport.get_session_id() method from the client streamable HTTP transport, along with the two stale TODO(Marcelo) comments about it.
Motivation and Context
The method existed to back the get_session_id callback that v1's streamable_http_client yielded as the third tuple element. That callback was already removed on main (documented in docs/migration.md), which left the getter with no callers in src/, tests/, or examples/ (it was # pragma: no cover) and no way to reach a transport instance through the public entry point anyway — streamable_http_client yields only the two streams.
The session_id attribute the getter wrapped is unchanged; it's the transport's own working state (header stamping, GET/DELETE gating, terminate-on-close).
How Has This Been Tested?
Existing client streamable HTTP tests pass. Also drove streamable_http_client end-to-end against a real MCPServer streamable HTTP app on a local port (initialize → tool call → DELETE on close) to confirm the client path is unaffected.
Breaking Changes
StreamableHTTPTransport.get_session_id() no longer exists. This was public in v1, so the removal is added to the existing "get_session_id callback removed from streamable_http_client" section of docs/migration.md, which already points users at httpx2 event hooks for capturing the session ID.
Types of changes
- Bug fix (non-breaking change which fixes an issue)
- New feature (non-breaking change which adds functionality)
- Breaking change (fix or feature that would cause existing functionality to change)
- Documentation update
Checklist
- I have read the MCP Documentation
- My code follows the repository's style guidelines
- New and existing tests pass locally
- I have added appropriate error handling
- I have added or updated documentation as needed
Additional context
No pragmas or type-ignores added; the removal drops one # pragma: no cover.