Expose RequestParams._meta in ClientSession.call_tool #1231

samchenatti · 2025-08-03T18:43:01Z

Motivation and Context

This change allow clients to send metadata through the _meta field as specified by the protocol.

It is important to expose _meta since there might be some metadata required by the server to control how the tool works (such as client preferences, its localization and so on). In some cases we also don't want the Agent/LLM to be aware of such data; it should be known by the MCP Host and Server only; therefore it cannot be exposed as tool usual arguments.

This feature has already been requested by me and another user - so it might benefit another people as well.

I also started a discussion about _meta being exposed by FastMCP Client, but they will wait until its implemented in here.

How Has This Been Tested?

I tested it on my local environment using a self-made MCP Server.

Since _meta is currently being used for progress report tokens, I also ensured this feature doesn't break progress_callback.

I'd be happy to implement the required unit-tests if someone can point the best test-file for it.

Breaking Changes

There are no breaking changes. The python-sdk already considers that _meta can carry data other than progressToken.

Also types.RequestParams.Meta model is already configured to allow extra key-values.

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

I decided to expose meta as a plain dict instead of types.RequestParams.Meta since, from my understanding, mcp.types shouldn't be exposed to final users.

Metadata could be exposed by another interfaces as well, such as list_tools, list_prompts and etc. I'm sticking with tool_call for now, but would be happy to replicate it to the other interfaces.

src/mcp/client/session.py

dsp-ant

I am okay with this change, but I think we should make the ordering such that it's BC compatbile, and create a follow up for the SDK version 2.0 to reconsider the ordering and force named arguments.

src/mcp/client/session.py

danielabonfim · 2025-08-07T19:06:35Z

This feature looks great and would be a valuable addition. Nice work! Would it be possible to get this approved for merge @dsp-ant

samchenatti · 2025-08-12T13:08:49Z

Hey, @dsp-ant!

Are there any other changes I need to make?

discorev · 2025-08-26T08:40:47Z

I'd also be interested in this, is there anything further that needs changing?

samchenatti · 2025-09-02T14:47:57Z

Hey, @dsp-ant, @ihrpr!

Is there anything else I need to fix in order to get this PR merged?

aadarshsingh191198 · 2025-09-10T13:59:47Z

I'd also be interested in this! Requesting maintainers to merge it if there are no unwanted side effects of this change.

maeryo · 2025-09-23T07:08:59Z

Great work @samchenatti! This feature would be really valuable for the MCP ecosystem. I hope the conflicts can be resolved soon and this PR gets merged. The community clearly supports this addition based on all the positive feedback. Keep up the excellent work! 🚀

felixweinberger

Feedback looks addressed to me but still requires some conflict resolution (apologies for the time it took to get back to this).

If you have time @samchenatti to update PR here and resolve conflicts that'd be greatly appreciated, otherwise I'll aim to get to it later this week!

samchenatti · 2025-09-23T11:14:17Z

Thanks for the feedback, @maeryo and @felixweinberger!

I'll fix the conflicts by the end of the day

samchenatti · 2025-09-23T12:55:14Z

@felixweinberger, @maeryo conflicts solved!

maeryo · 2025-09-24T12:51:56Z

cool! I also checked today and noticed that the kotlin-sdk didn’t have this implementation yet, so I submitted a PR with a similar approach to yours. In addition to just adding the meta parameter, I paid extra attention to improving validation logic as well.

modelcontextprotocol/kotlin-sdk#289

Jaorow · 2025-10-07T03:35:51Z

Hey @samchenatti
This is awesome and really helps out with something im trying to build!

Do you have an ETA on when this might be in?

samchenatti · 2025-10-07T10:46:42Z

Hey @Jaorow!

I'm waiting on the maintainers’ feedback...

This feature has become even more important since OpenAI announced the App SDK.
They’re making heavy use of _meta to enable UI components.

By merging this PR, we’d allow other MCP Clients to do the same.

maxisbey

Look good! Although, I'd want to see some unit tests for this. You could add them in tests/server/test_session.py

src/mcp/client/session.py

Jaorow · 2025-10-13T20:14:02Z

Hey @Jaorow!

I'm waiting on the maintainers’ feedback...

This feature has become even more important since OpenAI announced the App SDK. They’re making heavy use of _meta to enable UI components.

By merging this PR, we’d allow other MCP Clients to do the same.

@samchenatti Awesome, It will definitely open the door for more complex and structured functionality.

samchenatti · 2025-10-14T01:25:44Z

Hey, @maxisbey!

I made the requested changes and implemented the unit test.

~~I had to cheat a bit in the test and manually set _tool_output_schemas~~

After a good night’s sleep, I was able to properly implement the unit test (commit 2b61abba).

Now the client and server exchange all the necessary messages just like they would in a real scenario.

…rotocol phases

samchenatti · 2025-10-17T14:15:55Z

@maxisbey thanks for the approval!

@ihrpr, @dsp-ant can you guys also take a look on my changes?

dismissing my own review

…otocol#1231) Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com>

* Add regression test for stateless request memory cleanup (modelcontextprotocol#1140) * Implement RFC9728 - Support WWW-Authenticate header by MCP client (modelcontextprotocol#1071) * Add streamable HTTP starlette example to Python SDK docs (modelcontextprotocol#1111) * fix markdown error in README in main (modelcontextprotocol#1147) * README - replace code snippets with examples - add lowlevel to snippets (modelcontextprotocol#1150) * README - replace code snippets with examples - streamable http (modelcontextprotocol#1155) * chore: don't allow users to create issues outside the templates (modelcontextprotocol#1163) * Tests(cli): Add coverage for helper functions (modelcontextprotocol#635) * Docs: Update CallToolResult parsing in README (modelcontextprotocol#812) Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> * docs: add pre-commit install guide on CONTRIBUTING.md (modelcontextprotocol#995) Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> * fix flaky fix-test_streamablehttp_client_resumption test (modelcontextprotocol#1166) * README - replace code snippets with examples -- auth examples (modelcontextprotocol#1164) * Support falling back to OIDC metadata for auth (modelcontextprotocol#1061) * Add CODEOWNERS file for sdk (modelcontextprotocol#1169) * fix flaky test test_88_random_error (modelcontextprotocol#1171) * Make sure `RequestId` is not coerced as `int` (modelcontextprotocol#1178) * Fix: Replace threading.Lock with anyio.Lock for Ray deployment compatibility (modelcontextprotocol#1151) * fix: fix OAuth flow request object handling (modelcontextprotocol#1174) * update codeowners group (modelcontextprotocol#1191) * fix: perform auth server metadata discovery fallbacks on any 4xx (modelcontextprotocol#1193) * server: skip duplicate response on CancelledError (modelcontextprotocol#1153) Co-authored-by: ihrpr <inna@anthropic.com> * Unpack settings in FastMCP (modelcontextprotocol#1198) * chore: Remove unused prompt_manager.py file (modelcontextprotocol#1229) Co-authored-by: Tapan Chugh <tapanc@cs.washington.edu> * Improved supported for ProtectedResourceMetadata (modelcontextprotocol#1235) Co-authored-by: Paul Carleton <paulcarletonjr@gmail.com> * chore: Remove unused variable notification_options (modelcontextprotocol#1238) * Improve README around the Context object (modelcontextprotocol#1203) * fix: allow to pass `list[str]` to `token_endpoint_auth_signing_alg_values_supported` (modelcontextprotocol#1226) * Remove strict validation on `response_modes_supported` member of `OAuthMetadata` (modelcontextprotocol#1243) * Add pyright strict mode on the whole project (modelcontextprotocol#1254) * Consistent casing for default headers Accept and Content-Type (modelcontextprotocol#1263) * Update dependencies and fix type issues (modelcontextprotocol#1268) Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> * fix: prevent async generator cleanup errors in StreamableHTTP transport (modelcontextprotocol#1271) Co-authored-by: David Soria Parra <167242713+dsp-ant@users.noreply.github.com> * chore: uncomment .idea/ in .gitignore (modelcontextprotocol#1287) Co-authored-by: Claude <noreply@anthropic.com> * docs: clarify streamable_http_path configuration when mounting servers (modelcontextprotocol#1172) * feat: Add CORS configuration for browser-based MCP clients (modelcontextprotocol#1059) Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> * Added Audio to FastMCP (modelcontextprotocol#1130) * fix: avoid uncessary retries in OAuth authenticated requests (modelcontextprotocol#1206) Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> * Add PATHEXT to default STDIO env vars in windows (modelcontextprotocol#1256) * fix: error too many values to unpack (expected 2) (modelcontextprotocol#1279) Signed-off-by: San Nguyen <vinhsannguyen91@gmail.com> Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * SDK Parity: Avoid Parsing Server Response for non-JsonRPCMessage Requests (modelcontextprotocol#1290) * types: Setting default value for method: Literal (modelcontextprotocol#1292) * changes structured temperature to not deadly (modelcontextprotocol#1328) * Update simple-resource example to use non-deprecated read_resource return type (modelcontextprotocol#1331) Co-authored-by: Claude <noreply@anthropic.com> * docs: Update README to include link to API docs for modelcontextprotocol#1329 (modelcontextprotocol#1330) * Allow ping requests before initialization (modelcontextprotocol#1312) * Python lint: Ruff rules for pylint and code complexity (modelcontextprotocol#525) * Fix context injection for resources and prompts (modelcontextprotocol#1336) * fix(fastmcp): propagate mimeType in resource template list (modelcontextprotocol#1186) Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * fix: allow elicitations accepted without content (modelcontextprotocol#1285) Co-authored-by: Olivier Schiavo <olivier.schiavo@wengo.com> * Use --frozen in pre-commit config (modelcontextprotocol#1375) * Return HTTP 403 for invalid Origin headers (modelcontextprotocol#1353) * Add test for ProtectedResourceMetadataParsing (modelcontextprotocol#1236) Co-authored-by: Paul Carleton <paulcarletonjr@gmail.com> Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Fastmcp logging progress example (modelcontextprotocol#1270) Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * feat: add paginated list decorators for prompts, resources, and tools (modelcontextprotocol#1286) Co-authored-by: Claude <noreply@anthropic.com> * Remove "unconditionally" from conditional description (modelcontextprotocol#1289) * Use streamable-http consistently in examples (modelcontextprotocol#1389) * feat: Add SDK support for SEP-1034 default values in elicitation schemas (modelcontextprotocol#1337) Co-authored-by: Tapan Chugh <tapanc@cs.washington.edu> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Implementation of SEP 973 - Additional metadata + icons support (modelcontextprotocol#1357) * Add error log for client stdio (modelcontextprotocol#924) Co-authored-by: Your Name <youremail@yourdomain.com> Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Accept additional response_types values from OAuth servers (modelcontextprotocol#1323) * Issue 1379 patch - Fix MCP server OAuth not working with Visual Studio Code and others with extra grant_types (modelcontextprotocol#1380) * Add comprehensive Unicode tests for streamable HTTP transport (modelcontextprotocol#1381) * Update Icon.sizes to use string array format (modelcontextprotocol#1411) * Delete CODEOWNERS to eliminate notification overload (modelcontextprotocol#1413) * fix: fix the system message in simple-chatbot example (modelcontextprotocol#1394) * fix: improve misleading warning for progress callback exceptions (modelcontextprotocol#775) * fix: catch and rethrow SSEError during SSE connection establishment (modelcontextprotocol#975) Co-authored-by: zhangchuanhui <zhangchal@digitalchina.com> Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> * Add icons support for ResourceTemplate (modelcontextprotocol#1412) * Add documentation structure (modelcontextprotocol#1425) * Add documentation about testing (modelcontextprotocol#1426) * Improve OAuth protected resource metadata URL construction per RFC 9728 (modelcontextprotocol#1407) * feat: add ability to remove tools (modelcontextprotocol#1322) Co-authored-by: David Soria Parra <167242713+dsp-ant@users.noreply.github.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> Co-authored-by: Claude <noreply@anthropic.com> * Update README to link to Python SDK documentation (modelcontextprotocol#1430) * fix: update CLAUDE.md to remove auto-addition of reviewers. (modelcontextprotocol#1431) * [client] Implement MCP OAuth scope selection and step-up authorization (modelcontextprotocol#1324) * Handles message type Exception in lowlevel/server.py _handle_message function. Mentioned as TODO on line 528. (modelcontextprotocol#786) Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Fix workspace configuration error with structured_output_lowlevel.py (modelcontextprotocol#1471) Co-authored-by: lorenss-m <saeclmusic@gmail.com> * fix: Remove unnecessary constructor from ResourceServerSettings (modelcontextprotocol#1424) Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * feat: add resource annotations support to FastMCP (modelcontextprotocol#1468) * fix: send params as empty object for list methods without cursor (modelcontextprotocol#1453) * fix: Set the Server session initialization state immediately after respond… (modelcontextprotocol#1478) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> * feat: add tool metadata in FastMCP.tool decorator (modelcontextprotocol#1463) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> * Make client examples workspaces to reflect package code (modelcontextprotocol#1466) * Expose RequestParams._meta in ClientSession.call_tool (modelcontextprotocol#1231) Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Allow CallToolResult to be returned directly to support _meta field for OpenAI Apps (modelcontextprotocol#1459) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> * fix: uv CVE-2025-62518 astral-tokio-tar issue GHSA-j5gw-2vrg-8fgx (modelcontextprotocol#1505) * fix: use proper dependency resolution in CI (modelcontextprotocol#1507) * Upgrade GitHub Actions (modelcontextprotocol#1473) * test: use errno.ENOENT for command not found assertion (modelcontextprotocol#1498) * Replace deprecated dev-dependencies with dependency-groups (modelcontextprotocol#1488) Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * update uv to 0.9.5 (modelcontextprotocol#1510) * Relax Accept header requirement for JSON-only responses (modelcontextprotocol#1500) * fix: replace deprecated dev-dependencies in examples/clients (modelcontextprotocol#1518) * fix: Update spec links to new modelcontextprotocol.io location (modelcontextprotocol#1491) * fix: Replace fixed sleep with active server readiness check in SSE tests (modelcontextprotocol#1526) * fix: Replace arbitrary sleeps with active server readiness checks in tests (modelcontextprotocol#1527) Co-authored-by: Claude <noreply@anthropic.com> * Fix flaky timeout test in test_88_random_error (modelcontextprotocol#1525) * fix: Replace remaining manual server polling with wait_for_server helper (modelcontextprotocol#1529) * Implement RFC 7523 JWT flows (modelcontextprotocol#1247) Co-authored-by: Yann Jouanin <yann.jouanin@valueandco.com> * Fix pyright error and replace wildcard import with explicit imports (modelcontextprotocol#1532) * Fix auth client example URL handling for oauth provider (modelcontextprotocol#1549) * docs: use article "an" before "MCP" instead of "a" (modelcontextprotocol#1558) * Update Starlette to 0.49.1 in uv.lock (modelcontextprotocol#1559) * Fix typo in `ClientSessionGroup` doc string (modelcontextprotocol#1572) * Implement SEP-985: OAuth Protected Resource Metadata discovery fallback (modelcontextprotocol#1548) Co-authored-by: Claude <noreply@anthropic.com> Co-authored-by: Paul Carleton <paulc@anthropic.com> * Add --frozen flag to uv run commands in Claude config (modelcontextprotocol#1583) * Add get_server_capabilities() to ClientSession (modelcontextprotocol#1588) * Add everything-server for comprehensive MCP conformance testing (modelcontextprotocol#1587) * Get baseline 100% clean coverage (modelcontextprotocol#1553) * Add end-of-file-fixer pre-commit hook (modelcontextprotocol#1610) * Add coverage baseline commit to git-blame-ignore (modelcontextprotocol#1613) * Add SEP-1034 conformance test support to everything-server (modelcontextprotocol#1604) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> * refactor: extract OAuth helper functions and simplify provider state (modelcontextprotocol#1586) * Add client_id_metadata_document_supported to OAuthMetadata (modelcontextprotocol#1603) * Fix OAuth discovery fallback and URL ordering (modelcontextprotocol#1624) * Refactor `func_metadata()` implementation (modelcontextprotocol#1496) * Fix CI highest resolution test to actually test highest versions (modelcontextprotocol#1609) * feat: Pass through and expose additional parameters in `ClientSessionGroup.call_tool` and `.connect_to_server` (modelcontextprotocol#1576) * fix get_client_metadata_scopes on 401 (modelcontextprotocol#1631) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> * chore: Lazy import `jsonschema` library (modelcontextprotocol#1596) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> * docs: Update examples to use stateless HTTP with JSON responses (modelcontextprotocol#1499) * Add tests for JSON Schema 2020-12 field preservation (SEP-1613) (modelcontextprotocol#1649) * Add client_secret_basic authentication support (modelcontextprotocol#1334) Co-authored-by: Paul Carleton <paulc@anthropic.com> * Implement SEP-1577 - Sampling With Tools (modelcontextprotocol#1594) Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> Co-authored-by: Claude <noreply@anthropic.com> * SEP-1330: Elicitation Enum Schema Improvements and Standards Compliance (modelcontextprotocol#1246) Co-authored-by: Tapan Chugh <tapanc@cs.washington.edu> Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * [auth][conformance] add conformance auth client (modelcontextprotocol#1640) Co-authored-by: Claude <noreply@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Implement SEP-986: Tool name validation (modelcontextprotocol#1655) * fix: url for spec (modelcontextprotocol#1659) * feat: implement SEP-991 URL-based client ID (CIMD) support (modelcontextprotocol#1652) Co-authored-by: Claude <noreply@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Update doc string on custom_route (modelcontextprotocol#1660) * Implement SEP-1036: URL mode elicitation for secure out-of-band interactions (modelcontextprotocol#1580) Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> * Skip empty SSE data to avoid parsing errors (modelcontextprotocol#1670) * SEP-1686: Tasks (modelcontextprotocol#1645) * Add on_session_created callback option (modelcontextprotocol#1710) * Add SSE polling support (SEP-1699) (modelcontextprotocol#1654) * Support client_credentials flow with JWT and Basic auth (modelcontextprotocol#1663) Co-authored-by: Claude <noreply@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * feat: backwards-compatible create_message overloads for SEP-1577 (modelcontextprotocol#1713) * Merge commit from fork * Auto-enable DNS rebinding protection for localhost servers When a FastMCP server is created with host="127.0.0.1" or "localhost" and no explicit transport_security is provided, automatically enable DNS rebinding protection. Both 127.0.0.1 and localhost are allowed as valid hosts/origins since clients may use either to connect. * Add tests for auto DNS rebinding protection on localhost Tests verify that: - Protection auto-enables for host=127.0.0.1 - Protection auto-enables for host=localhost - Both 127.0.0.1 and localhost are in allowed hosts/origins - Protection does NOT auto-enable for other hosts (e.g., 0.0.0.0) - Explicit transport_security settings are not overridden * Add IPv6 localhost (::1) support for DNS rebinding protection Extend auto-enable DNS rebinding protection to also cover IPv6 localhost. When host="::1", protection is now auto-enabled with appropriate allowed hosts ([::1]:*) and origins (http://[::1]:*). * Fix import ordering in test file * chore: update LATEST_PROTOCOL_VERSION to 2025-11-25 (modelcontextprotocol#1715) * fix: add lifespan context manager to StreamableHTTP mounting examples (modelcontextprotocol#1669) Co-authored-by: TheMailmans <tyler@example.com> Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> * fix: handle ClosedResourceError in StreamableHTTP message router (modelcontextprotocol#1384) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> * fix: skip priming events and close_sse_stream for old protocol versions (modelcontextprotocol#1719) * refactor(auth): remove unused _register_client method (modelcontextprotocol#1748) * [MCP-266] Add tests for Gumloop server extensions * Fix uv workspace config for gumloop-mcp package name * Sync with upstream MCP SDK and fix merge conflicts * Fix tool cache timing and missing properties check in server.py * Fix coverage and add proper type annotations for Gumloop extensions * Version up * Skip README code example tests (Gumloop README has no code snippets) --------- Signed-off-by: San Nguyen <vinhsannguyen91@gmail.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> Co-authored-by: yurikunash <143175350+yurikunash@users.noreply.github.com> Co-authored-by: Pamela Fox <pamela.fox@gmail.com> Co-authored-by: Inna Harper <inna.hrpr@gmail.com> Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> Co-authored-by: Ian Davenport <49379192+davenpi@users.noreply.github.com> Co-authored-by: Dagang Wei <functicons@gmail.com> Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> Co-authored-by: Stanley Law <stanleylkal@gmail.com> Co-authored-by: Luca Chang <131398524+LucaButBoring@users.noreply.github.com> Co-authored-by: leweng <leweng@nvidia.com> Co-authored-by: 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<84836280+dragonier23@users.noreply.github.com> Co-authored-by: keurcien <keurcien.luu@gmail.com> Co-authored-by: Tim Esler <tim.esler@gmail.com> Co-authored-by: San Nguyen <22189661+sandangel@users.noreply.github.com> Co-authored-by: Justin Wang <89049861+justin-yi-wang@users.noreply.github.com> Co-authored-by: jess <jessachandler@gmail.com> Co-authored-by: Peter Alexander <pja@anthropic.com> Co-authored-by: Reid Geyer <12072650+reidg44@users.noreply.github.com> Co-authored-by: Eleftheria Stein-Kousathana <eleftheria.kousathana@gmail.com> Co-authored-by: Christian Clauss <cclauss@me.com> Co-authored-by: pchoudhury22 <pchoudhury22@apple.com> Co-authored-by: owengo <owengo@users.noreply.github.com> Co-authored-by: Olivier Schiavo <olivier.schiavo@wengo.com> Co-authored-by: Steve Billings <billings.steve@gmail.com> Co-authored-by: Mike Salvatore <mike.s.salvatore@gmail.com> Co-authored-by: pengwa <pengwa@microsoft.com> Co-authored-by: Your Name <youremail@yourdomain.com> Co-authored-by: Jon Shea <jonshea@jonshea.com> Co-authored-by: automaton82 <terrence.sheflin@gmail.com> Co-authored-by: Yukuan Jia <jiayukuan@huawei.com> Co-authored-by: Lorenzo <lorenzo_cesconeto@hotmail.com> Co-authored-by: ZhangChuanhui <57099533+zhangch-ss@users.noreply.github.com> Co-authored-by: zhangchuanhui <zhangchal@digitalchina.com> Co-authored-by: Marcus Shu <46469249+shulkx@users.noreply.github.com> Co-authored-by: Brandon Wu <49291449+brandonspark@users.noreply.github.com> Co-authored-by: Dogacan Colak <dogacancolak@gmail.com> Co-authored-by: AishwaryaKalloli <30429206+AishwaryaKalloli@users.noreply.github.com> Co-authored-by: lorenss-m <saeclmusic@gmail.com> Co-authored-by: Rocky Haotian Du <2712479005@qq.com> Co-authored-by: Fenn Bailey <fennb@users.noreply.github.com> Co-authored-by: daamitt <147169947+daamitt@users.noreply.github.com> Co-authored-by: Mat Leonard <137834585+mat-octave@users.noreply.github.com> Co-authored-by: Samuel Felipe Chenatti <samuel.chenatti@gmail.com> Co-authored-by: Brandon Shar <6599653+BrandonShar@users.noreply.github.com> Co-authored-by: mingo007 <maoqiming1@huawei.com> Co-authored-by: adam jones <domdomegg+git@gmail.com> Co-authored-by: Yann Jouanin <yann.jouanin@valueandco.com> Co-authored-by: Koichi ITO <koic.ito@gmail.com> Co-authored-by: Cole Murray <colemurray.cs@gmail.com> Co-authored-by: inaku <63503085+inaku-Gyan@users.noreply.github.com> Co-authored-by: Chris Coutinho <12901868+cbcoutinho@users.noreply.github.com> Co-authored-by: Paul Carleton <paulc@anthropic.com> Co-authored-by: Camila Rondinini <camila@anthropic.com> Co-authored-by: Victorien <65306057+Viicos@users.noreply.github.com> Co-authored-by: Andrii Blyzniuk <bliznyuk.andrey@gmail.com> Co-authored-by: Liang Wu <18244712+wuliang229@users.noreply.github.com> Co-authored-by: adam jones <adamj+git@anthropic.com> Co-authored-by: Olivier Chafik <ochafik@anthropic.com> Co-authored-by: Tyler Mailman <themailmaninbox@gmail.com> Co-authored-by: TheMailmans <tyler@example.com> Co-authored-by: Edison <Edison.A.N@hotmail.com>

* Add regression test for stateless request memory cleanup (modelcontextprotocol#1140) * Implement RFC9728 - Support WWW-Authenticate header by MCP client (modelcontextprotocol#1071) * Add streamable HTTP starlette example to Python SDK docs (modelcontextprotocol#1111) * fix markdown error in README in main (modelcontextprotocol#1147) * README - replace code snippets with examples - add lowlevel to snippets (modelcontextprotocol#1150) * README - replace code snippets with examples - streamable http (modelcontextprotocol#1155) * chore: don't allow users to create issues outside the templates (modelcontextprotocol#1163) * Tests(cli): Add coverage for helper functions (modelcontextprotocol#635) * Docs: Update CallToolResult parsing in README (modelcontextprotocol#812) Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> * docs: add pre-commit install guide on CONTRIBUTING.md (modelcontextprotocol#995) Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> * fix flaky fix-test_streamablehttp_client_resumption test (modelcontextprotocol#1166) * README - replace code snippets with examples -- auth examples (modelcontextprotocol#1164) * Support falling back to OIDC metadata for auth (modelcontextprotocol#1061) * Add CODEOWNERS file for sdk (modelcontextprotocol#1169) * fix flaky test test_88_random_error (modelcontextprotocol#1171) * Make sure `RequestId` is not coerced as `int` (modelcontextprotocol#1178) * Fix: Replace threading.Lock with anyio.Lock for Ray deployment compatibility (modelcontextprotocol#1151) * fix: fix OAuth flow request object handling (modelcontextprotocol#1174) * update codeowners group (modelcontextprotocol#1191) * fix: perform auth server metadata discovery fallbacks on any 4xx (modelcontextprotocol#1193) * server: skip duplicate response on CancelledError (modelcontextprotocol#1153) Co-authored-by: ihrpr <inna@anthropic.com> * Unpack settings in FastMCP (modelcontextprotocol#1198) * chore: Remove unused prompt_manager.py file (modelcontextprotocol#1229) Co-authored-by: Tapan Chugh <tapanc@cs.washington.edu> * Improved supported for ProtectedResourceMetadata (modelcontextprotocol#1235) Co-authored-by: Paul Carleton <paulcarletonjr@gmail.com> * chore: Remove unused variable notification_options (modelcontextprotocol#1238) * Improve README around the Context object (modelcontextprotocol#1203) * fix: allow to pass `list[str]` to `token_endpoint_auth_signing_alg_values_supported` (modelcontextprotocol#1226) * Remove strict validation on `response_modes_supported` member of `OAuthMetadata` (modelcontextprotocol#1243) * Add pyright strict mode on the whole project (modelcontextprotocol#1254) * Consistent casing for default headers Accept and Content-Type (modelcontextprotocol#1263) * Update dependencies and fix type issues (modelcontextprotocol#1268) Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> * fix: prevent async generator cleanup errors in StreamableHTTP transport (modelcontextprotocol#1271) Co-authored-by: David Soria Parra <167242713+dsp-ant@users.noreply.github.com> * chore: uncomment .idea/ in .gitignore (modelcontextprotocol#1287) Co-authored-by: Claude <noreply@anthropic.com> * docs: clarify streamable_http_path configuration when mounting servers (modelcontextprotocol#1172) * feat: Add CORS configuration for browser-based MCP clients (modelcontextprotocol#1059) Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> * Added Audio to FastMCP (modelcontextprotocol#1130) * fix: avoid uncessary retries in OAuth authenticated requests (modelcontextprotocol#1206) Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> * Add PATHEXT to default STDIO env vars in windows (modelcontextprotocol#1256) * fix: error too many values to unpack (expected 2) (modelcontextprotocol#1279) Signed-off-by: San Nguyen <vinhsannguyen91@gmail.com> Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * SDK Parity: Avoid Parsing Server Response for non-JsonRPCMessage Requests (modelcontextprotocol#1290) * types: Setting default value for method: Literal (modelcontextprotocol#1292) * changes structured temperature to not deadly (modelcontextprotocol#1328) * Update simple-resource example to use non-deprecated read_resource return type (modelcontextprotocol#1331) Co-authored-by: Claude <noreply@anthropic.com> * docs: Update README to include link to API docs for modelcontextprotocol#1329 (modelcontextprotocol#1330) * Allow ping requests before initialization (modelcontextprotocol#1312) * Python lint: Ruff rules for pylint and code complexity (modelcontextprotocol#525) * Fix context injection for resources and prompts (modelcontextprotocol#1336) * fix(fastmcp): propagate mimeType in resource template list (modelcontextprotocol#1186) Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * fix: allow elicitations accepted without content (modelcontextprotocol#1285) Co-authored-by: Olivier Schiavo <olivier.schiavo@wengo.com> * Use --frozen in pre-commit config (modelcontextprotocol#1375) * Return HTTP 403 for invalid Origin headers (modelcontextprotocol#1353) * Add test for ProtectedResourceMetadataParsing (modelcontextprotocol#1236) Co-authored-by: Paul Carleton <paulcarletonjr@gmail.com> Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Fastmcp logging progress example (modelcontextprotocol#1270) Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * feat: add paginated list decorators for prompts, resources, and tools (modelcontextprotocol#1286) Co-authored-by: Claude <noreply@anthropic.com> * Remove "unconditionally" from conditional description (modelcontextprotocol#1289) * Use streamable-http consistently in examples (modelcontextprotocol#1389) * feat: Add SDK support for SEP-1034 default values in elicitation schemas (modelcontextprotocol#1337) Co-authored-by: Tapan Chugh <tapanc@cs.washington.edu> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Implementation of SEP 973 - Additional metadata + icons support (modelcontextprotocol#1357) * Add error log for client stdio (modelcontextprotocol#924) Co-authored-by: Your Name <youremail@yourdomain.com> Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Accept additional response_types values from OAuth servers (modelcontextprotocol#1323) * Issue 1379 patch - Fix MCP server OAuth not working with Visual Studio Code and others with extra grant_types (modelcontextprotocol#1380) * Add comprehensive Unicode tests for streamable HTTP transport (modelcontextprotocol#1381) * Update Icon.sizes to use string array format (modelcontextprotocol#1411) * Delete CODEOWNERS to eliminate notification overload (modelcontextprotocol#1413) * fix: fix the system message in simple-chatbot example (modelcontextprotocol#1394) * fix: improve misleading warning for progress callback exceptions (modelcontextprotocol#775) * fix: catch and rethrow SSEError during SSE connection establishment (modelcontextprotocol#975) Co-authored-by: zhangchuanhui <zhangchal@digitalchina.com> Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> * Add icons support for ResourceTemplate (modelcontextprotocol#1412) * Add documentation structure (modelcontextprotocol#1425) * Add documentation about testing (modelcontextprotocol#1426) * Improve OAuth protected resource metadata URL construction per RFC 9728 (modelcontextprotocol#1407) * feat: add ability to remove tools (modelcontextprotocol#1322) Co-authored-by: David Soria Parra <167242713+dsp-ant@users.noreply.github.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> Co-authored-by: Claude <noreply@anthropic.com> * Update README to link to Python SDK documentation (modelcontextprotocol#1430) * fix: update CLAUDE.md to remove auto-addition of reviewers. (modelcontextprotocol#1431) * [client] Implement MCP OAuth scope selection and step-up authorization (modelcontextprotocol#1324) * Handles message type Exception in lowlevel/server.py _handle_message function. Mentioned as TODO on line 528. (modelcontextprotocol#786) Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Fix workspace configuration error with structured_output_lowlevel.py (modelcontextprotocol#1471) Co-authored-by: lorenss-m <saeclmusic@gmail.com> * fix: Remove unnecessary constructor from ResourceServerSettings (modelcontextprotocol#1424) Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * feat: add resource annotations support to FastMCP (modelcontextprotocol#1468) * fix: send params as empty object for list methods without cursor (modelcontextprotocol#1453) * fix: Set the Server session initialization state immediately after respond… (modelcontextprotocol#1478) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> * feat: add tool metadata in FastMCP.tool decorator (modelcontextprotocol#1463) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> * Make client examples workspaces to reflect package code (modelcontextprotocol#1466) * Expose RequestParams._meta in ClientSession.call_tool (modelcontextprotocol#1231) Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Allow CallToolResult to be returned directly to support _meta field for OpenAI Apps (modelcontextprotocol#1459) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> * fix: uv CVE-2025-62518 astral-tokio-tar issue GHSA-j5gw-2vrg-8fgx (modelcontextprotocol#1505) * fix: use proper dependency resolution in CI (modelcontextprotocol#1507) * Upgrade GitHub Actions (modelcontextprotocol#1473) * test: use errno.ENOENT for command not found assertion (modelcontextprotocol#1498) * Replace deprecated dev-dependencies with dependency-groups (modelcontextprotocol#1488) Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * update uv to 0.9.5 (modelcontextprotocol#1510) * Relax Accept header requirement for JSON-only responses (modelcontextprotocol#1500) * fix: replace deprecated dev-dependencies in examples/clients (modelcontextprotocol#1518) * fix: Update spec links to new modelcontextprotocol.io location (modelcontextprotocol#1491) * fix: Replace fixed sleep with active server readiness check in SSE tests (modelcontextprotocol#1526) * fix: Replace arbitrary sleeps with active server readiness checks in tests (modelcontextprotocol#1527) Co-authored-by: Claude <noreply@anthropic.com> * Fix flaky timeout test in test_88_random_error (modelcontextprotocol#1525) * fix: Replace remaining manual server polling with wait_for_server helper (modelcontextprotocol#1529) * Implement RFC 7523 JWT flows (modelcontextprotocol#1247) Co-authored-by: Yann Jouanin <yann.jouanin@valueandco.com> * Fix pyright error and replace wildcard import with explicit imports (modelcontextprotocol#1532) * Fix auth client example URL handling for oauth provider (modelcontextprotocol#1549) * docs: use article "an" before "MCP" instead of "a" (modelcontextprotocol#1558) * Update Starlette to 0.49.1 in uv.lock (modelcontextprotocol#1559) * Fix typo in `ClientSessionGroup` doc string (modelcontextprotocol#1572) * Implement SEP-985: OAuth Protected Resource Metadata discovery fallback (modelcontextprotocol#1548) Co-authored-by: Claude <noreply@anthropic.com> Co-authored-by: Paul Carleton <paulc@anthropic.com> * Add --frozen flag to uv run commands in Claude config (modelcontextprotocol#1583) * Add get_server_capabilities() to ClientSession (modelcontextprotocol#1588) * Add everything-server for comprehensive MCP conformance testing (modelcontextprotocol#1587) * Get baseline 100% clean coverage (modelcontextprotocol#1553) * Add end-of-file-fixer pre-commit hook (modelcontextprotocol#1610) * Add coverage baseline commit to git-blame-ignore (modelcontextprotocol#1613) * Add SEP-1034 conformance test support to everything-server (modelcontextprotocol#1604) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> * refactor: extract OAuth helper functions and simplify provider state (modelcontextprotocol#1586) * Add client_id_metadata_document_supported to OAuthMetadata (modelcontextprotocol#1603) * Fix OAuth discovery fallback and URL ordering (modelcontextprotocol#1624) * Refactor `func_metadata()` implementation (modelcontextprotocol#1496) * Fix CI highest resolution test to actually test highest versions (modelcontextprotocol#1609) * feat: Pass through and expose additional parameters in `ClientSessionGroup.call_tool` and `.connect_to_server` (modelcontextprotocol#1576) * fix get_client_metadata_scopes on 401 (modelcontextprotocol#1631) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> * chore: Lazy import `jsonschema` library (modelcontextprotocol#1596) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> * docs: Update examples to use stateless HTTP with JSON responses (modelcontextprotocol#1499) * Add tests for JSON Schema 2020-12 field preservation (SEP-1613) (modelcontextprotocol#1649) * Add client_secret_basic authentication support (modelcontextprotocol#1334) Co-authored-by: Paul Carleton <paulc@anthropic.com> * Implement SEP-1577 - Sampling With Tools (modelcontextprotocol#1594) Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> Co-authored-by: Claude <noreply@anthropic.com> * SEP-1330: Elicitation Enum Schema Improvements and Standards Compliance (modelcontextprotocol#1246) Co-authored-by: Tapan Chugh <tapanc@cs.washington.edu> Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * [auth][conformance] add conformance auth client (modelcontextprotocol#1640) Co-authored-by: Claude <noreply@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Implement SEP-986: Tool name validation (modelcontextprotocol#1655) * fix: url for spec (modelcontextprotocol#1659) * feat: implement SEP-991 URL-based client ID (CIMD) support (modelcontextprotocol#1652) Co-authored-by: Claude <noreply@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * Update doc string on custom_route (modelcontextprotocol#1660) * Implement SEP-1036: URL mode elicitation for secure out-of-band interactions (modelcontextprotocol#1580) Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> * Skip empty SSE data to avoid parsing errors (modelcontextprotocol#1670) * SEP-1686: Tasks (modelcontextprotocol#1645) * Add on_session_created callback option (modelcontextprotocol#1710) * Add SSE polling support (SEP-1699) (modelcontextprotocol#1654) * Support client_credentials flow with JWT and Basic auth (modelcontextprotocol#1663) Co-authored-by: Claude <noreply@anthropic.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> * feat: backwards-compatible create_message overloads for SEP-1577 (modelcontextprotocol#1713) * Merge commit from fork * Auto-enable DNS rebinding protection for localhost servers When a FastMCP server is created with host="127.0.0.1" or "localhost" and no explicit transport_security is provided, automatically enable DNS rebinding protection. Both 127.0.0.1 and localhost are allowed as valid hosts/origins since clients may use either to connect. * Add tests for auto DNS rebinding protection on localhost Tests verify that: - Protection auto-enables for host=127.0.0.1 - Protection auto-enables for host=localhost - Both 127.0.0.1 and localhost are in allowed hosts/origins - Protection does NOT auto-enable for other hosts (e.g., 0.0.0.0) - Explicit transport_security settings are not overridden * Add IPv6 localhost (::1) support for DNS rebinding protection Extend auto-enable DNS rebinding protection to also cover IPv6 localhost. When host="::1", protection is now auto-enabled with appropriate allowed hosts ([::1]:*) and origins (http://[::1]:*). * Fix import ordering in test file * chore: update LATEST_PROTOCOL_VERSION to 2025-11-25 (modelcontextprotocol#1715) * fix: add lifespan context manager to StreamableHTTP mounting examples (modelcontextprotocol#1669) Co-authored-by: TheMailmans <tyler@example.com> Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> * fix: handle ClosedResourceError in StreamableHTTP message router (modelcontextprotocol#1384) Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> * fix: skip priming events and close_sse_stream for old protocol versions (modelcontextprotocol#1719) * refactor(auth): remove unused _register_client method (modelcontextprotocol#1748) * [MCP-266] Add tests for Gumloop server extensions * Fix uv workspace config for gumloop-mcp package name * Sync with upstream MCP SDK and fix merge conflicts * Fix tool cache timing and missing properties check in server.py * Fix coverage and add proper type annotations for Gumloop extensions * Version up * Skip README code example tests (Gumloop README has no code snippets) * Support gumloop and mcp outptuschema * Add publish tools to dev dependencies and update README for uv --------- Signed-off-by: San Nguyen <vinhsannguyen91@gmail.com> Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com> Co-authored-by: yurikunash <143175350+yurikunash@users.noreply.github.com> Co-authored-by: Pamela Fox <pamela.fox@gmail.com> Co-authored-by: Inna Harper <inna.hrpr@gmail.com> Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com> Co-authored-by: Ian Davenport <49379192+davenpi@users.noreply.github.com> Co-authored-by: Dagang Wei <functicons@gmail.com> Co-authored-by: Felix Weinberger <fweinberger@anthropic.com> Co-authored-by: Stanley Law <stanleylkal@gmail.com> Co-authored-by: Luca Chang <131398524+LucaButBoring@users.noreply.github.com> Co-authored-by: leweng <leweng@nvidia.com> Co-authored-by: Clare Liguori <liguori@amazon.com> Co-authored-by: lukacf <luka@peltarion.com> Co-authored-by: ihrpr <inna@anthropic.com> Co-authored-by: Tapan Chugh <chugh.tapan@gmail.com> Co-authored-by: Tapan Chugh <tapanc@cs.washington.edu> Co-authored-by: Yann Jouanin <4557670+yannj-fr@users.noreply.github.com> Co-authored-by: Paul Carleton <paulcarletonjr@gmail.com> Co-authored-by: Sreenath Somarajapuram <somarajapuram@gmail.com> Co-authored-by: Omer Korner <omerkorner@gmail.com> Co-authored-by: joesavage-silabs <159480754+joesavage-silabs@users.noreply.github.com> Co-authored-by: Gregory L <gregory.linford@mistral.ai> Co-authored-by: David Soria Parra <167242713+dsp-ant@users.noreply.github.com> Co-authored-by: Moustapha Ebnou <155577789+mous222@users.noreply.github.com> Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com> Co-authored-by: Claude <noreply@anthropic.com> Co-authored-by: Jerome <jerome@anthropic.com> Co-authored-by: xavier <84836280+dragonier23@users.noreply.github.com> Co-authored-by: keurcien <keurcien.luu@gmail.com> Co-authored-by: Tim Esler <tim.esler@gmail.com> Co-authored-by: San Nguyen <22189661+sandangel@users.noreply.github.com> Co-authored-by: Justin Wang <89049861+justin-yi-wang@users.noreply.github.com> Co-authored-by: jess <jessachandler@gmail.com> Co-authored-by: Peter Alexander <pja@anthropic.com> Co-authored-by: Reid Geyer <12072650+reidg44@users.noreply.github.com> Co-authored-by: Eleftheria Stein-Kousathana <eleftheria.kousathana@gmail.com> Co-authored-by: Christian Clauss <cclauss@me.com> Co-authored-by: pchoudhury22 <pchoudhury22@apple.com> Co-authored-by: owengo <owengo@users.noreply.github.com> Co-authored-by: Olivier Schiavo <olivier.schiavo@wengo.com> Co-authored-by: Steve Billings <billings.steve@gmail.com> Co-authored-by: Mike Salvatore <mike.s.salvatore@gmail.com> Co-authored-by: pengwa <pengwa@microsoft.com> Co-authored-by: Your Name <youremail@yourdomain.com> Co-authored-by: Jon Shea <jonshea@jonshea.com> Co-authored-by: automaton82 <terrence.sheflin@gmail.com> Co-authored-by: Yukuan Jia <jiayukuan@huawei.com> Co-authored-by: Lorenzo <lorenzo_cesconeto@hotmail.com> Co-authored-by: ZhangChuanhui <57099533+zhangch-ss@users.noreply.github.com> Co-authored-by: zhangchuanhui <zhangchal@digitalchina.com> Co-authored-by: Marcus Shu <46469249+shulkx@users.noreply.github.com> Co-authored-by: Brandon Wu <49291449+brandonspark@users.noreply.github.com> Co-authored-by: Dogacan Colak <dogacancolak@gmail.com> Co-authored-by: AishwaryaKalloli <30429206+AishwaryaKalloli@users.noreply.github.com> Co-authored-by: lorenss-m <saeclmusic@gmail.com> Co-authored-by: Rocky Haotian Du <2712479005@qq.com> Co-authored-by: Fenn Bailey <fennb@users.noreply.github.com> Co-authored-by: daamitt <147169947+daamitt@users.noreply.github.com> Co-authored-by: Mat Leonard <137834585+mat-octave@users.noreply.github.com> Co-authored-by: Samuel Felipe Chenatti <samuel.chenatti@gmail.com> Co-authored-by: Brandon Shar <6599653+BrandonShar@users.noreply.github.com> Co-authored-by: mingo007 <maoqiming1@huawei.com> Co-authored-by: adam jones <domdomegg+git@gmail.com> Co-authored-by: Yann Jouanin <yann.jouanin@valueandco.com> Co-authored-by: Koichi ITO <koic.ito@gmail.com> Co-authored-by: Cole Murray <colemurray.cs@gmail.com> Co-authored-by: inaku <63503085+inaku-Gyan@users.noreply.github.com> Co-authored-by: Chris Coutinho <12901868+cbcoutinho@users.noreply.github.com> Co-authored-by: Paul Carleton <paulc@anthropic.com> Co-authored-by: Camila Rondinini <camila@anthropic.com> Co-authored-by: Victorien <65306057+Viicos@users.noreply.github.com> Co-authored-by: Andrii Blyzniuk <bliznyuk.andrey@gmail.com> Co-authored-by: Liang Wu <18244712+wuliang229@users.noreply.github.com> Co-authored-by: adam jones <adamj+git@anthropic.com> Co-authored-by: Olivier Chafik <ochafik@anthropic.com> Co-authored-by: Tyler Mailman <themailmaninbox@gmail.com> Co-authored-by: TheMailmans <tyler@example.com> Co-authored-by: Edison <Edison.A.N@hotmail.com> Co-authored-by: dvlpjrs <dvlp.jrs@gmail.com>

feat: expose RequestParams._meta in ClientSession.call_tool

7750c5f

samchenatti requested review from a team and ihrpr August 3, 2025 18:43

style: apply ruff format

16a171f

samchenatti commented Aug 4, 2025

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samchenatti added 2 commits August 4, 2025 13:24

refactor: make _meta handling more readable

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fix: reorder meta argument to avoid a BC

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samchenatti requested a review from dsp-ant August 4, 2025 18:08

samchenatti mentioned this pull request Aug 4, 2025

Allow clients to send _meta to server jlowin/fastmcp#1315

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jdecker76 mentioned this pull request Aug 14, 2025

Resume tokens for long-running operations modelcontextprotocol/modelcontextprotocol#1003

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PeriniM mentioned this pull request Sep 20, 2025

InjectedState in MCP tools langchain-ai/langchain-mcp-adapters#287

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felixweinberger added the needs more work Not ready to be merged yet, needs additional follow-up from the author(s). label Sep 23, 2025

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felixweinberger added the needs maintainer action Potentially serious issue - needs proactive fix and maintainer attention label Sep 23, 2025

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felixweinberger added needs sync and removed needs more work Not ready to be merged yet, needs additional follow-up from the author(s). labels Sep 23, 2025

Merge branch 'main' into expose_meta_in_tool_calling

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samchenatti force-pushed the expose_meta_in_tool_calling branch from 82f9320 to f021dec Compare September 23, 2025 12:50

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felixweinberger mentioned this pull request Oct 3, 2025

Expose _meta in ClientSession methods #1216

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Expose _meta in ClientSession methods #1216

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felixweinberger linked an issue Oct 7, 2025 that may be closed by this pull request

SDK doesn't support specifying tool metadata? #1224

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felixweinberger mentioned this pull request Oct 7, 2025

SDK doesn't support specifying tool metadata? #1224

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codefromthecrypt mentioned this pull request Oct 13, 2025

MCP request.params._meta support for envoyproxy/ai-gateway#1348

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samchenatti added 3 commits October 13, 2025 21:01

Use RequestParams.Meta for _meta in call_tool

8f2ebb6

Implement test to assert _meta behavior in tool call

05e6b27

Use default CallToolRequest.method value in call_tool

796938e

Include None case for test_client_tool_call_with_meta

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samchenatti force-pushed the expose_meta_in_tool_calling branch from 0315b04 to 701611d Compare October 14, 2025 01:36

felixweinberger requested a review from maxisbey October 14, 2025 09:54

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Reimplement test_client_tool_call_with_meta to goes through all the p…

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…rotocol phases

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Merge branch 'main' into expose_meta_in_tool_calling

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maxisbey merged commit 40acbc5 into modelcontextprotocol:main Oct 17, 2025
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aiorga-sherpas mentioned this pull request Oct 22, 2025

Add meta to call tool jlowin/fastmcp#2206

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0Delta pushed a commit to 0Delta/python-sdk that referenced this pull request Nov 27, 2025

Expose RequestParams._meta in ClientSession.call_tool (modelcontextpr…

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…otocol#1231) Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com>

Expose RequestParams._meta in ClientSession.call_tool #1231

Expose RequestParams._meta in ClientSession.call_tool #1231

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samchenatti commented Aug 3, 2025

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