fastmcp/docs/servers
Jeremiah Lowin 0ba3db1a56
Mirror the frontend's protocol era on a proxy's backend connection (#4573)
* Mirror front protocol era onto proxy backend connection

A proxy created from a non-Client target now negotiates, on its backend,
whatever era its front client negotiated, instead of pinning one era.
Explicit create_proxy(mode=...) still overrides. Guards the eager backend
initialize() so an explicit modern pin behind a handshake front no longer
crashes.

* Carry the mirrored proxy era into multi-server config backends

A multi-server MCPConfig target mounts one proxy per configured server on a
composite router, so setting the era on the outer client stopped at the router
and every real backend stayed on its default era. TransportOptions.backend_mode
carries it down, resolved per request alongside the outer mirroring.

The router is also sealed under a policy held on the transport rather than a
fresh per-router ephemeral key, so a guard tool's request_state survives the
router being rebuilt between rounds.
2026-07-20 12:31:02 -04:00
..
auth Add server-side identity assertion (SEP-990 ID-JAG) (#4483) 2026-07-18 19:52:15 -04:00
providers Mirror the frontend's protocol era on a proxy's backend connection (#4573) 2026-07-20 12:31:02 -04:00
transforms feat(code-mode): default sandbox limits and per-execution tool-call cap (#4170) 2026-05-20 10:47:12 -04:00
authorization.mdx Support async auth checks (#3152) 2026-02-11 12:48:51 -05:00
composition.mdx Align server component docs (#4260) 2026-07-19 14:23:36 -04:00
context.mdx Align server component docs (#4260) 2026-07-19 14:23:36 -04:00
dependency-injection.mdx Align server component docs (#4260) 2026-07-19 14:23:36 -04:00
elicitation.mdx Fix stale MRTR/elicitation framing in client and upgrade docs (#4551) 2026-07-19 18:10:15 -04:00
icons.mdx Document icon theme support (#4537) 2026-07-18 20:57:36 -04:00
lifespan.mdx Restructure documentation for FastMCP 3.0 (#2951) 2026-01-19 21:33:35 -05:00
logging.mdx Restructure documentation for FastMCP 3.0 (#2951) 2026-01-19 21:33:35 -05:00
middleware.mdx Run FastMCP middleware for every inbound message (#4553) 2026-07-19 20:29:08 -04:00
pagination.mdx Align server component docs (#4260) 2026-07-19 14:23:36 -04:00
progress.mdx Align server component docs (#4260) 2026-07-19 14:23:36 -04:00
prompts.mdx Align server component docs (#4260) 2026-07-19 14:23:36 -04:00
resources.mdx Align server component docs (#4260) 2026-07-19 14:23:36 -04:00
sampling.mdx docs: quote pip extras install examples (#4568) 2026-07-20 11:09:50 -04:00
server.mdx Align server component docs (#4260) 2026-07-19 14:23:36 -04:00
storage-backends.mdx Fix broken code examples in docs (#3869) 2026-04-12 12:53:04 -04:00
tasks.mdx Speed up the unit test suite, and fix the task-notification race it surfaced (#4550) 2026-07-19 18:52:04 -04:00
telemetry.mdx Align server component docs (#4260) 2026-07-19 14:23:36 -04:00
testing.mdx Restructure docs navigation: CLI section, Composition, More (#3361) 2026-03-02 21:09:48 -05:00
tool-fingerprinting.mdx docs: add tool fingerprinting recipe for stable schema hashing (#4233) 2026-05-27 10:52:14 -04:00
tools.mdx Align server component docs (#4260) 2026-07-19 14:23:36 -04:00
versioning.mdx Align server component docs (#4260) 2026-07-19 14:23:36 -04:00
visibility.mdx Align server component docs (#4260) 2026-07-19 14:23:36 -04:00