ec5b2258c9
Cut import and startup cost with deferred model builds and lazy imports
...
Every import path now pays only for what it uses, with no public API
added or removed:
- The protocol models (mcp.types / mcp_types, incl. the JSON-RPC
envelopes and the generated per-version wire packages) build their
pydantic validators on first use instead of at import (defer_build),
through one shared private base class. First-use builds are
serialised behind a single process-wide lock, since released pydantic
does not make concurrent first use of a deferred model thread-safe;
this also fixes a pre-existing concurrent-first-use failure that
reproduces on main.
- `import mcp` binds the client/server names lazily on first attribute
access (PEP 562) instead of importing both stacks eagerly, and the
client no longer imports the server, so client entry points stop
loading the server, the web stack, httpx2 and cryptography.
- The web application stack (starlette's app machinery, sse_starlette,
uvicorn) loads with the app builders that use it, and each protocol
version's wire package loads on the first message parsed for that
version rather than both loading at import.
On the fresh-interpreter harness `import mcp` is ~0.4x of v1 (main is
~1.6x), the client entry points ~0.6x of v1, `import mcp.server.mcpserver`
~0.7x, and time-to-ready / stdio cold start land at parity with v1. RSS
after `import mcp` is 19 MiB (v1 43.5, main 57). Steady-state per-call
latency is unchanged.
Observable-but-incidental differences (removed incidental namespace
bindings, deeper submodules no longer imported as a side effect of a
bare `import mcp`, get_type_hints needing localns= for a documented set
of callables, pre-first-use introspection) are catalogued in
docs/migration.md; ratchet tests pin the import footprints and the
concurrent-first-use safety.
2026-08-03 15:06:11 +00:00
c9c431b71a
Expose the middleware chain on MCPServer and stop sending unrequested change notifications ( #3201 )
2026-07-28 12:24:23 +01:00
528e366558
Fail fast on server-to-client requests in JSON-response mode instead of hanging ( #3195 )
2026-07-28 11:04:51 +01:00
89c5e700f2
Gate log notifications on the per-request log-level opt-in at 2026-07-28 ( #3198 )
2026-07-28 02:20:33 +01:00
923341c98a
Stop answering cancelled requests ( #3188 )
2026-07-27 23:26:00 +01:00
11934c90ae
Replace FileResource.is_binary with an encoding field ( #3171 )
2026-07-26 00:58:06 +01:00
814072c94d
Narrow message_handler's parameter to notifications and exceptions ( #3168 )
2026-07-26 00:24:48 +01:00
629ca297d2
Isolate the stdio server's stdin and stdout from handler subprocesses ( #3117 )
2026-07-25 13:05:51 +01:00
00a70148bc
Serve the 2026-07-28 protocol over stdio: decide the era from the opening request ( #3152 )
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2026-07-24 13:46:37 +01:00
837ef904f8
Align with spec #3002 : optional clientInfo, serverInfo in result _meta ( #3143 )
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2026-07-23 12:00:36 +01:00
03aaebd3aa
Add Streamable HTTP request body limits ( #3095 )
2026-07-16 08:33:32 +02:00
2713b53b12
Replace httpx and httpx-sse with httpx2 ( #2972 )
...
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Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com >
2026-07-14 17:05:08 +01:00
867bba6263
Share one event loop per test module to stop Windows socketpair churn ( #3070 )
2026-07-07 13:19:04 +01:00
d287c9868f
Extend resolver DI to sampling and roots requests ( #3049 )
2026-07-06 18:25:57 +01:00
220d362112
docs: restructure into topical sections and add the four most-asked-for pages ( #3044 )
2026-07-01 21:06:04 +01:00
080f2a869d
Harden the dual-era stream loop's era-lock and rejection semantics ( #3040 )
2026-07-01 17:07:12 +01:00
e50fb5be19
Serve the 2026-07-28 era over stdio and other stream-pair transports ( #3038 )
2026-07-01 00:11:56 +01:00
ca10dade2c
Serve subscriptions/listen with a pluggable event bus (SEP-2575) ( #3035 )
2026-06-30 23:01:04 +01:00
48ef569f7e
Validate Mcp-Param-* headers server-side on the 2026-07-28 HTTP path (SEP-2243) ( #3033 )
2026-06-30 21:39:32 +01:00
4df609119f
Add a client extension API ( #3034 )
2026-06-30 21:31:02 +01:00
7322ca56f4
Require integrity protection for MRTR requestState ( #3032 )
2026-06-30 21:30:32 +01:00
b15b1d5f07
Add a client-side response cache honoring SEP-2549 caching hints ( #3023 )
2026-06-30 11:31:06 +01:00
8d0f928e40
Pass InputRequiredResult through the MCPServer prompt and resource pipelines ( #3020 )
2026-06-29 16:50:58 +01:00
8f2c97b769
Consult request_state only for the question a resolver is asking ( #3019 )
2026-06-29 16:44:05 +01:00
533c6a8226
Add cache_hints constructor map for SEP-2549 caching hints ( #3015 )
2026-06-29 14:11:15 +00:00
c85836a081
Drive resolver elicitation over the 2026-07-28 input_required flow ( #2986 )
...
Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com >
2026-06-29 14:39:43 +01:00
f664db8952
Add resolver dependency injection for MCPServer tools ( #2969 )
...
Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com >
2026-06-29 11:51:46 +01:00
4b519782f1
Add a pluggable server extension API with MCP Apps ( #3003 )
...
Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com >
2026-06-29 10:58:05 +01:00
24717cc8eb
feat: RFC 6570 URI templates with operator-aware security ( #2356 )
2026-06-26 20:29:17 +02:00
067f90578c
Add SSE response mode to the 2026 streamable-HTTP server entry ( #3001 )
2026-06-26 19:09:08 +02:00
c0ecb70e24
Support RFC 8693 token exchange for enterprise IdP flows (SEP-990) ( #2988 )
...
Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com >
2026-06-26 17:57:10 +02:00
08b62308d4
Client auto-resolves InputRequiredResult via existing callbacks (SEP-2322) ( #2998 )
2026-06-26 17:35:23 +02:00
3945bdde11
Remove the dispatch-tier middleware hook ( #2997 )
2026-06-26 17:08:16 +02:00
b31d95a429
Make OpenTelemetry tracing the single default middleware ( #2995 )
2026-06-26 15:47:37 +02:00
f41a5193f3
Preserve empty issuer/resource paths on AuthSettings ( #2987 )
2026-06-26 11:41:41 +02:00
587340279e
Conformance burn-down: server-side InputRequiredResult, Mcp-Method/Name validation, x-mcp-header filter (14 scenarios → green) ( #2974 )
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2026-06-26 09:51:59 +02:00
0ee7f1b293
Split protocol types into a standalone mcp-types package ( #2973 )
2026-06-25 19:18:38 +02:00
96bf22e57a
Stop flagging snake_case is_error results as tool errors in OTel span ( #2971 )
2026-06-25 15:24:45 +00:00
1b1abf6ab6
Add GenAI semantic-convention attributes to OpenTelemetryMiddleware ( #2970 )
2026-06-25 14:43:54 +00:00
f226d00d0a
Client-side 2026-07-28 support: .discover()/.adopt() + Client(mode=); request-metadata green ( #2950 )
2026-06-25 16:09:23 +02:00
a527142312
Buffer per-request StreamableHTTP streams to avoid serial-router head-of-line block ( #2934 )
2026-06-22 16:20:45 +01:00
ad81ca234a
Slim ServerMiddleware to (ctx, call_next) and add OpenTelemetryMiddleware ( #2941 )
...
Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com >
2026-06-22 14:46:30 +01:00
2397319a68
Server-side 2026-07-28 stateless support: classifier, driver split, server/discover ( #2928 )
2026-06-21 19:34:17 +01:00
4573e4ac33
Deprecate roots, sampling, and logging methods per SEP-2577 ( #2926 )
2026-06-20 18:25:41 +02:00
fda4c54362
fix: correct MCPServer call_tool result type ( #2816 )
...
Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com >
2026-06-20 16:56:16 +02:00
f253682393
Return -32602 for resource not found (SEP-2164) ( #2920 )
2026-06-20 16:55:23 +02:00
84bf9bde05
First end-to-end 2026-07-28 stateless tools/call (experimental entry + ClientSession pin) ( #2917 )
2026-06-20 14:55:59 +01:00
510832aa45
Re-vendor 2026-07-28 schema and absorb spec #2907 error-code renumber ( #2912 )
2026-06-19 15:46:15 +01:00
734746a3d9
Resolve protocol version per request and expose it as ctx.protocol_version ( #2886 )
2026-06-17 08:46:42 +01:00
65be5a7147
Protocol types for 2026-07-28: superset monolith, committed per-version packages, and wire-method maps ( #2849 )
2026-06-16 17:40:14 +01:00
Max Isbey