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
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
837ef904f8
Align with spec #3002 : optional clientInfo, serverInfo in result _meta ( #3143 )
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2026-07-23 12:00:36 +01:00
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
d287c9868f
Extend resolver DI to sampling and roots requests ( #3049 )
2026-07-06 18:25:57 +01:00
ca10dade2c
Serve subscriptions/listen with a pluggable event bus (SEP-2575) ( #3035 )
2026-06-30 23:01:04 +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
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
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 )
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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 )
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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
08b62308d4
Client auto-resolves InputRequiredResult via existing callbacks (SEP-2322) ( #2998 )
2026-06-26 17:35:23 +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
f226d00d0a
Client-side 2026-07-28 support: .discover()/.adopt() + Client(mode=); request-metadata green ( #2950 )
2026-06-25 16:09:23 +02:00
ad81ca234a
Slim ServerMiddleware to (ctx, call_next) and add OpenTelemetryMiddleware ( #2941 )
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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 )
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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
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
1012d60004
[v2] ClientSession runs on JSONRPCDispatcher; BaseSession removed ( #2838 )
2026-06-15 14:46:34 +01:00
bdc48e98b1
Fix stdio client shutdown bugs and rebuild the stdio test suite ( #2773 )
2026-06-05 16:15:43 +01:00
8cc187fac0
Remove Tasks (SEP-1686) from the SDK ( #2714 )
2026-06-02 18:27:05 +02:00
3eb579948a
Add subject and claims to AccessToken ( #2686 )
2026-05-26 13:13:55 +00:00
c5f12ec1e9
Add resources parameter to MCPServer ( #2414 )
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Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com >
2026-04-12 14:42:12 +02:00
3ce0f76e6e
Don't block the event loop on sync resource and prompt functions ( #2380 )
2026-03-31 13:43:56 -04:00
3517a29c82
feat(server): restore dependencies parameter on MCPServer ( #2358 )
2026-03-27 13:42:15 +00:00
20dd94632e
feat(client): store InitializeResult as initialize_result ( #2300 )
2026-03-18 17:31:26 +00:00
7826ade12b
test: convert test_integration.py to in-memory transport (fix flaky) ( #2277 )
2026-03-18 15:25:11 +00:00
31a38b5078
fix: correct Context type parameters across examples and tests ( #2256 )
2026-03-09 16:52:56 +00:00
92f1b1500d
fix: remove MIME type validation from MCPServer Resource ( #2235 )
2026-03-06 14:50:58 +00:00
cc22bf5464
refactor: remove request_ctx ContextVar, thread Context explicitly ( #2203 )
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Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com >
2026-03-04 13:23:02 +00:00
fc57c2c4c5
test: fix progress notification assertions for related_request_id ( #2038 )
...
Co-authored-by: Lee Hubbard <hubbard.zlee@unknowncyber.com >
Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com >
2026-02-18 11:53:03 +00:00
0a22a9dc33
refactor: replace lowlevel Server decorators with on_* constructor kwargs ( #1985 )
2026-02-12 15:55:54 +00:00
4fc49c62bd
feat: add ClientRequestContext type alias for client-side handlers ( #1989 )
2026-02-03 17:37:38 +01:00
b1f7eec3cd
refactor: split RequestContext between server and client ( #1987 )
2026-02-03 14:35:07 +01:00
21822053df
Support different transports in Client ( #1972 )
2026-01-30 12:11:27 +00:00
14744c66c5
Add tests for MCPServer.read_resource exception handling ( #1957 )
2026-01-27 13:49:06 +01:00
acba5478a9
refactor: McpError renamed to MCPError and flatten parameters ( #1956 )
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Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com >
2026-01-26 14:37:44 +01:00
65c614e48e
Rename FastMCP to MCPServer ( #1951 )
2026-01-25 14:45:52 +01:00
Max Isbey