## Why
Subagents should be able to use known HTTP MCP tool definitions without opening a connection until a tool is actually called.
## What changed
- Add streamable HTTP configurations to the process-scoped MCP tool catalog cache when their authentication identity can be derived safely.
- Fingerprint transport settings, relevant environment variables, protocol mode, plugin status, and client capabilities so catalogs are reused only across equivalent connections.
- Keep OAuth and other dynamically resolved credential configurations out of the shared cache.
## Testing
- Add an integration test proving that a subagent receives cached HTTP tools without reinitializing the server, then starts its own connection when it calls one.
GitOrigin-RevId: bb2787e29e9b71993def31aafd1f0d8f1b728d26