Changelog - FastMCP

v2.12.2

2025-09-03

v2.12.2: Perchance to StreamThis is a hotfix for a bug where the streamable-http transport was not recognized as a valid option in fastmcp.json configuration files, despite being supported by the CLI. This resulted in a parsing error when the CLI arguments were merged against the configuration spec.

What’s Changed

Fixes 🐞

Fix streamable-http transport validation in fastmcp.json config by @jlowin in #1739

Full Changelog: v2.12.1…v2.12.2

v2.12.1

2025-09-03

v2.12.1: OAuth to JoyFastMCP 2.12.1 strengthens the OAuth proxy implementation based on extensive community testing and feedback. This release improves client storage reliability, adds PKCE forwarding for enhanced security, introduces configurable token endpoint authentication methods, and expands scope handling—all addressing real-world integration challenges discovered since 2.12.0. The enhanced test suite with mock providers ensures these improvements are robust and maintainable.

Breaking Changes

OAuth Proxy: Users of built-in IDP integrations should note that resource_server_url has been renamed to base_url for clarity and consistency

What’s Changed

Enhancements 🔧

Make openai dependency optional by @jlowin in #1701
Remove orphaned OAuth proxy code by @jlowin in #1722
Expose valid scopes from OAuthProxy metadata by @dmikusa in #1717
OAuth proxy PKCE forwarding by @jlowin in #1733
Add token_endpoint_auth_method parameter to OAuthProxy by @jlowin in #1736
Clean up and enhance OAuth proxy tests with mock provider by @jlowin in #1738

Fixes 🐞

refactor: replace auth provider registry with ImportString by @jlowin in #1710
Fix OAuth resource URL handling and WWW-Authenticate header by @jlowin in #1706
Fix OAuth proxy client storage and add retry logic by @jlowin in #1732

Docs 📚

Fix documentation: use StreamableHttpTransport for headers in testing by @jlowin in #1702
docs: add performance warnings for mounted servers and proxies by @strawgate in #1669
Update documentation around scopes for google by @jlowin in #1703
Add deployment information to quickstart by @seanpwlms in #1433
Update quickstart by @jlowin in #1728
Add development docs for FastMCP by @jlowin in #1719

Other Changes 🦾

Set generics without bounds to default=Any by @strawgate in #1648

New Contributors

@dmikusa made their first contribution in #1717
@seanpwlms made their first contribution in #1433

Full Changelog: v2.12.0…v2.12.1

v2.12.0

2025-08-31

v2.12.0: Auth to the RacesFastMCP 2.12 represents one of our most significant releases to date, both in scope and community involvement. After extensive testing and iteration with the community, we’re shipping major improvements to authentication, configuration, and MCP feature adoption.🔐 OAuth Proxy for Broader Provider Support addresses a fundamental challenge: while MCP requires Dynamic Client Registration (DCR), many popular OAuth providers don’t support it. The new OAuth proxy bridges this gap, enabling FastMCP servers to authenticate with providers like GitHub, Google, WorkOS, and Azure through minimal configuration. These native integrations ship today, with more providers planned based on community needs.📋 Declarative JSON Configuration introduces a standardized, portable way to describe and deploy MCP servers. The fastmcp.json configuration file becomes the single source of truth for dependencies, transport settings, entrypoints, and server metadata. This foundation sets the stage for future capabilities like transformations and remote sources, moving toward a world where MCP servers are as portable and shareable as container images.🧠 Sampling API Fallback tackles the chicken-and-egg problem limiting adoption of advanced MCP features. Sampling—where servers request LLM completions from clients—is powerful but underutilized due to limited client support. FastMCP now lets server authors define fallback handlers that generate sampling completions server-side when clients don’t support the feature, encouraging adoption while maintaining compatibility.This release took longer than usual to ship, and for good reason: the community’s aggressive testing and feedback on the authentication system helped us reach a level of stability we’re confident in. There’s certainly more work ahead, but these foundations position FastMCP to handle increasingly complex use cases while remaining approachable for developers.Thank you to our new contributors and everyone who tested preview builds. Your feedback directly shaped these features.

What’s Changed

New Features 🎉

Add OAuth proxy that allows authentication with social IDPs without DCR support by @jlowin in #1434
feat: introduce declarative JSON configuration system by @jlowin in #1517
✨ Fallback to a Completions API when Sampling is not available by @strawgate in #1145
Implement typed source system for FastMCP declarative configuration by @jlowin in #1607

Enhancements 🔧

Support importing custom_route endpoints when mounting servers by @jlowin in #1470
Remove unnecessary asserts by @jlowin in #1484
Add Claude issue triage by @jlowin in #1510
Inline dedupe prompt by @jlowin in #1512
Improve stdio and mcp_config clean-up by @strawgate in #1444
involve kwargs to pass parameters on creating RichHandler for logging customization. by @itaru2622 in #1504
Move SDK docs generation to post-merge workflow by @jlowin in #1513
Improve label triage guidance by @jlowin in #1516
Add code review guidelines for agents by @jlowin in #1520
Remove trailing slash in unit tests by @jlowin in #1535
Update OAuth callback UI branding by @jlowin in #1536
Fix Marvin workflow to support development tools by @jlowin in #1537
Add mounted_components_raise_on_load_error setting for debugging by @jlowin in #1534
feat: Add —workspace flag to fastmcp install cursor by @jlowin in #1522
switch from pyright to ty by @zzstoatzz in #1545
feat: trigger Marvin workflow on PR body content by @jlowin in #1549
Add WorkOS and Azure OAuth providers by @jlowin in #1550
Adjust timeout for slow MCP Server shutdown test by @strawgate in #1561
Update banner by @jlowin in #1567
Added import of AuthProxy to auth init by @KaliszS in #1568
Add configurable redirect URI validation for OAuth providers by @jlowin in #1582
Remove invalid-argument-type ignore and fix type errors by @jlowin in #1588
Remove generate-schema from public CLI by @jlowin in #1591
Skip flaky windows test / mulit-client garbage collection by @jlowin in #1592
Add setting to disable logging configuration by @isra17 in #1575
Improve debug logging for nested Servers / Clients by @strawgate in #1604
Add GitHub pull request template by @strawgate in #1581
chore: Automate docs and schema updates via PRs by @jlowin in #1611
Experiment with haiku for limited workflows by @jlowin in #1613
feat: Improve GitHub workflow automation for schema and SDK docs by @jlowin in #1615
Consolidate server loading logic into FileSystemSource by @jlowin in #1614
Prevent Haiku Marvin from commenting when there are no duplicates by @jlowin in #1622
chore: Add clarifying note to automated PR bodies by @jlowin in #1623
feat: introduce inline snapshots by @strawgate in #1605
Improve fastmcp.json environment configuration and project-based deployments by @jlowin in #1631
fix: allow passing query params in OAuthProxy upstream authorization url by @danb27 in #1630
Support multiple —with-editable flags in CLI commands by @jlowin in #1634
feat: support comma separated oauth scopes by @jlowin in #1642
Add allowed_client_redirect_uris to OAuth provider subclasses by @jlowin in #1662
Consolidate CLI config parsing and prevent infinite loops by @jlowin in #1660
Internal refactor: mcp server config by @jlowin in #1672
Refactor Environment to support multiple runtime types by @jlowin in #1673
Add type field to Environment base class by @jlowin in #1676

Fixes 🐞

Fix breaking change: restore output_schema=False compatibility by @jlowin in #1482
Fix #1506: Update tool filtering documentation from _meta to meta by @maybenotconnor in #1511
Fix pytest warnings by @jlowin in #1559
nest schemas under assets by @jlowin in #1593
Skip flaky windows test by @jlowin in #1596
ACTUALLY move schemas to fastmcp.json by @jlowin in #1597
Fix and centralize CLI path resolution by @jlowin in #1590
Remove client info modifications by @jlowin in #1620
Fix $defs being discarded in input schema of transformed tool by @pldesch-chift in #1578
Fix enum elicitation to use inline schemas for MCP compatibility by @jlowin in #1632
Reuse session for StdioTransport in Client.new by @strawgate in #1635
Feat: Configurable LoggingMiddleware payload serialization by @vl-kp in #1636
Fix OAuth redirect URI validation for DCR compatibility by @jlowin in #1661
Add default scope handling in OAuth proxy by @romanusyk in #1667
Fix OAuth token expiry handling by @jlowin in #1671
Add resource_server_url parameter to OAuth proxy providers by @jlowin in #1682

Breaking Changes 🛫

Enhance inspect command with structured output and format options by @jlowin in #1481

Docs 📚

Update changelog by @jlowin in #1453
Update banner by @jlowin in #1472
Update logo files by @jlowin in #1473
Update deployment docs by @jlowin in #1486
Update FastMCP Cloud screenshot by @jlowin in #1487
Update authentication note in docs by @jlowin in #1488
chore: Update installation.mdx version snippet by @thomas-te in #1496
Update fastmcp cloud server requirements by @jlowin in #1497
Fix oauth pyright type checking by @strawgate in #1498
docs: Fix type annotation in return value documentation by @MaikelVeen in #1499
Fix PromptMessage usage in docs example by @jlowin in #1515
Create CODE_OF_CONDUCT.md by @jlowin in #1523
Fixed wrong import path in new docs page by @KaliszS in #1538
Document symmetric key JWT verification support by @jlowin in #1586
Update fastmcp.json schema path by @jlowin in #1595

Dependencies 📦

Bump actions/create-github-app-token from 1 to 2 by @dependabot[bot] in #1436
Bump astral-sh/setup-uv from 4 to 6 by @dependabot[bot] in #1532
Bump actions/checkout from 4 to 5 by @dependabot[bot] in #1533

Other Changes 🦾

Add dedupe workflow by @jlowin in #1454
Update AGENTS.md by @jlowin in #1471
Give Marvin the power of the Internet by @strawgate in #1475
Update just error message for static checks by @jlowin in #1483
Remove labeler by @jlowin in #1509
update aproto server to handle rich links by @zzstoatzz in #1556
fix: enable triage bot for fork PRs using pull_request_target by @jlowin in #1557

New Contributors

@thomas-te made their first contribution in #1496
@maybenotconnor made their first contribution in #1511
@MaikelVeen made their first contribution in #1499
@KaliszS made their first contribution in #1538
@isra17 made their first contribution in #1575
@marvin-context-protocol[bot] made their first contribution in #1616
@pldesch-chift made their first contribution in #1578
@vl-kp made their first contribution in #1636
@romanusyk made their first contribution in #1667

Full Changelog: v2.11.3…v2.12.0

v2.11.3

2025-08-11

v2.11.3: API-tite for ChangeThis release includes significant enhancements to the experimental OpenAPI parser and fixes a significant bug that led schemas not to be included in input/output schemas if they were transitive dependencies (e.g. A → B → C implies A depends on C). For users naively transforming large OpenAPI specs into MCP servers, this may result in ballooning payload sizes and necessitate curation.

What’s Changed

Enhancements 🔧

Improve redirect handling to address 307’s by @jlowin in #1387
Ensure resource + template names are properly prefixed when importing/mounting by @jlowin in #1423
fixes #1398: Add JWT claims to AccessToken by @panargirakis in #1399
Enable Protected Resource Metadata to provide resource_name and resou… by @yannj-fr in #1371
Pin mcp SDK under 2.0 to avoid breaking changes by @jlowin in #1428
Clean up complexity from PR #1426 by @jlowin in #1435
Optimize OpenAPI payload size by 46% by @jlowin in #1452
Update static checks by @jlowin in #1448

Fixes 🐞

Fix client-side logging bug #1394 by @chi2liu in #1397
fix: Fix httpx_client_factory type annotation to match MCP SDK (#1402) by @chi2liu in #1405
Fix OpenAPI allOf handling at requestBody top level (#1378) by @chi2liu in #1425
Fix OpenAPI transitive references and performance (#1372) by @jlowin in #1426
fix(type): lifespan is partially unknown by @ykun9 in #1389
Ensure transformed tools generate structured content by @jlowin in #1443

Docs 📚

docs(client/logging): reflect corrected default log level mapping by @jlowin in #1403
Add documentation for get_access_token() dependency function by @jlowin in #1446

Other Changes 🦾

Add comprehensive tests for utilities.components module by @chi2liu in #1395
Consolidate agent instructions into AGENTS.md by @jlowin in #1404
Fix performance test threshold to prevent flaky failures by @jlowin in #1406
Update agents.md; add github instructions by @jlowin in #1410
Add Marvin assistant by @jlowin in #1412
Marvin: fix deprecated variable names by @jlowin in #1417
Simplify action setup and add github tools for Marvin by @jlowin in #1419
Update marvin workflow name by @jlowin in #1421
Improve GitHub templates by @jlowin in #1422

New Contributors

@panargirakis made their first contribution in #1399
@ykun9 made their first contribution in #1389
@yannj-fr made their first contribution in #1371

Full Changelog: v2.11.2…v2.11.3

v2.11.2

2025-08-06

v2.11.2: Satis-factory

What’s Changed

Enhancements 🔧

Support factory functions in fastmcp run by @jlowin in #1384
Add async support to client_factory in FastMCPProxy (#1286) by @bianning in #1375

Fixes 🐞

Fix server_version field in inspect manifest by @jlowin in #1383
Fix Settings field with both default and default_factory by @jlowin in #1380

Other Changes 🦾

Remove unused arg by @jlowin in #1382
Add remote auth provider tests by @jlowin in #1351

New Contributors

@bianning made their first contribution in #1375

Full Changelog: v2.11.1…v2.11.2

v2.11.1

2025-08-04

v2.11.1: You’re Better Auth Now

What’s Changed

New Features 🎉

Introduce RemoteAuthProvider for cleaner external identity provider integration, update docs by @jlowin in #1346

Enhancements 🔧

perf: optimize string operations in OpenAPI parameter processing by @chi2liu in #1342

Fixes 🐞

Fix method-bound FunctionTool schemas by @strawgate in #1360
Manually set _key after model_copy() to enable prefixing Transformed Tools by @strawgate in #1357

Docs 📚

Docs updates by @jlowin in #1336
Add 2.11 to changelog by @jlowin in #1337
Update AuthKit vocab by @jlowin in #1338
Fix typo in decorating-methods.mdx by @Ozzuke in #1344

New Contributors

@Ozzuke made their first contribution in #1344

Full Changelog: v2.11.0…v2.11.1

v2.11.0

2025-08-01

v2.11.0: Auth to a Good Start

FastMCP 2.11 doubles down on what developers need most: speed and simplicity. This massive release delivers significant performance improvements and a dramatically better developer experience.🔐 Enterprise-Ready Authentication brings comprehensive OAuth 2.1 support with WorkOS’s AuthKit integration. The new AuthProvider interface leverages MCP’s support for separate resource and authorization servers, handling API keys and remote authentication with Dynamic Client Registration. AuthKit integration means you can plug into existing enterprise identity systems without rebuilding your auth stack, setting the stage for plug-and-play auth that doesn’t require users to become security experts overnight.⚡ The Experimental OpenAPI Parser delivers dramatic performance improvements through single-pass schema processing and optimized memory usage. OpenAPI integrations are now significantly faster, with cleaner, more maintainable code. (Note: the experimental parser is disabled by default, set FASTMCPEXPERIMENTALENABLENEWOPENAPIPARSER=1 to enable it. A message will be shown to all users on the legacy parser encouraging them to try the new one before it becomes the default.)🧠 Context State Management finally gives you persistent state across tool calls with a simple dict interface, while enhanced meta support lets you expose rich component metadata to clients. Combined with improved type annotations, string-based argument descriptions, and UV transport support, this release makes FastMCP feel more intuitive than ever.This release represents a TON of community contributions and sets the foundation for even more ambitious features ahead.

What’s Changed

New Features 🎉

Introduce experimental OpenAPI parser with improved performance and maintainability by @jlowin in #1209
Add state dict to Context (#1118) by @mukulmurthy in #1160
Expose FastMCP tags to clients via component meta dict by @jlowin in #1281
Add _fastmcp meta namespace by @jlowin in #1290
Add TokenVerifier protocol support alongside existing OAuthProvider authentication by @jlowin in #1297
Add comprehensive OAuth 2.1 authentication system with WorkOS integration by @jlowin in #1327

Enhancements 🔧

[🐶] Transform MCP Server Tools by @strawgate in #1132
Add —python, —project, and —with-requirements options to CLI commands by @jlowin in #1190
Support fastmcp run mcp.json by @strawgate in #1138
Support from future import annotations by @jlowin in #1199
Optimize OpenAPI parser performance with single-pass schema processing by @jlowin in #1214
Log tool name on transform validation error by @strawgate in #1238
Refactor get_http_request and context.session_id by @hopeful0 in #1242
Support creating tool argument descriptions from string annotations by @jlowin in #1255
feat: Add Annotations support for resources and resource templates by @chughtapan in #1260
Add UV Transport by @strawgate in #1270
Improve OpenAPI-to-JSONSchema conversion utilities by @jlowin in #1283
Ensure proxy components forward meta dicts by @jlowin in #1282
fix: server argument passing in CLI run command by @chughtapan in #1293
Add meta support to tool transformation utilities by @jlowin in #1295
feat: Allow Resource Metadata URL as field in OAuthProvider by @dacamposol in #1287
Use a simple overwrite instead of a merge for meta by @jlowin in #1296
Remove unused TimedCache by @strawgate in #1303
refactor: standardize logging usage across OpenAPI utilities by @chi2liu in #1322
perf: optimize OpenAPI parsing by reducing dict copy operations by @chi2liu in #1321
Structured client-side logging by @cjermain in #1326

Fixes 🐞

fix: preserve def reference when referenced in allOf / oneOf / anyOf by @algirdasci in #1208
fix: add type hint to custom_route decorator by @zzstoatzz in #1210
chore: typo by @richardkmichael in #1216
fix: handle non-string $ref values in experimental OpenAPI parser by @jlowin in #1217
Skip repeated type conversion and validation in proxy client elicitation handler by @chughtapan in #1222
Ensure default fields are not marked nullable by @jlowin in #1224
Fix stateful proxy client mixing in multi-proxies sessions by @hopeful0 in #1245
Fix invalid async context manager usage in proxy documentation by @zzstoatzz in #1246
fix: experimental FastMCPOpenAPI server lost headers in request when init(client with headers) by @itaru2622 in #1254
Fix typing, add tests for tool call middleware by @jlowin in #1269
Fix: prune hidden parameter defs by @muhammadkhalid-03 in #1257
Fix nullable field handling in OpenAPI to JSON Schema conversion by @jlowin in #1279
Ensure fastmcp run supports v1 servers by @jlowin in #1332

Breaking Changes 🛫

Change server flag to —name by @jlowin in #1248

Docs 📚

Remove unused import from FastAPI integration documentation by @mariotaddeucci in #1194
Update fastapi docs by @jlowin in #1198
Add docs for context state management by @jlowin in #1227
Permit.io integration docs by @orweis in #1226
Update docs to reflect sync tools by @jlowin in #1234
Update changelog.mdx by @jlowin in #1235
Update SDK docs by @jlowin in #1236
Update —name flag documentation for Cursor/Claude by @adam-conway in #1239
Add annotations docs by @jlowin in #1268
Update openapi/fastapi URLs README.md by @jbn in #1278
Add 2.11 version badge for state management by @jlowin in #1289
Add meta parameter support to tools, resources, templates, and prompts decorators by @jlowin in #1294
docs: update get_state and set_state references by @Maxi91f in #1306
Add unit tests and docs for denying tool calls with middleware by @jlowin in #1333
Remove reference to stacked decorators by @jlowin in #1334
Eunomia authorization server can run embedded within the MCP server by @tommitt in #1317

Other Changes 🦾

Update README.md by @jlowin in #1230
Logcapture addition to test_server file by @Sourav-Tripathy in #1229
Add tests for headers with both legacy and experimental openapi parser by @jlowin in #1259
Small clean-up from MCP Tool Transform PR by @strawgate in #1267
Add test for proxy tags visibility by @jlowin in #1302
Add unit test for sampling with image messages by @jlowin in #1329
Remove redundant resource_metadata_url assignment by @jlowin in #1328
Update bug.yml by @jlowin in #1331
Ensure validation errors are raised when masked by @jlowin in #1330

New Contributors

@mariotaddeucci made their first contribution in #1194
@algirdasci made their first contribution in #1208
@chughtapan made their first contribution in #1222
@mukulmurthy made their first contribution in #1160
@orweis made their first contribution in #1226
@Sourav-Tripathy made their first contribution in #1229
@adam-conway made their first contribution in #1239
@muhammadkhalid-03 made their first contribution in #1257
@jbn made their first contribution in #1278
@dacamposol made their first contribution in #1287
@chi2liu made their first contribution in #1322
@cjermain made their first contribution in #1326

Full Changelog: v2.10.6…v2.11.0

v2.10.6

2025-07-19

v2.10.6: Hymn for the Weekend

A special Saturday release with many fixes.

What’s Changed

Enhancements 🔧

Resolve #1139 — Implement include_context argument in Context.sample by @codingjoe in #1141
feat(settings): add log level normalization by @ka2048 in #1171
add server name to mounted server warnings by @artificial-aidan in #1147
Add StatefulProxyClient by @hopeful0 in #1109

Fixes 🐞

Fix OpenAPI empty parameters by @FabrizioSandri in #1128
Fix title field preservation in tool transformations by @jlowin in #1131
Fix optional parameter validation in OpenAPI integration by @jlowin in #1135
Do not silently exclude the “context” key from JSON body by @melkamar in #1153
Fix tool output schema generation to respect Pydantic serialization aliases by @zzstoatzz in #1148
fix: _replace_ref_with_defs; ensure ref_path is string by @itaru2622 in #1164
Fix nesting when making OpenAPI arrays and objects optional by @melkamar in #1178
Fix mcp-json output format to include server name by @jlowin in #1185
Only configure logging one time by @jlowin in #1187

Docs 📚

Update changelog.mdx by @jlowin in #1127
Eunomia Authorization with native FastMCP’s Middleware by @tommitt in #1144
update api ref for new mdxify version by @zzstoatzz in #1182

Other Changes 🦾

Expand empty parameter filtering and add comprehensive tests by @jlowin in #1129
Add no-commit-to-branch hook by @zzstoatzz in #1149
Update README.md by @jlowin in #1165
skip on rate limit by @zzstoatzz in #1183
Remove deprecated proxy creation by @jlowin in #1186
Separate integration tests from unit tests in CI by @jlowin in #1188

New Contributors

@FabrizioSandri made their first contribution in #1128
@melkamar made their first contribution in #1153
@codingjoe made their first contribution in #1141
@itaru2622 made their first contribution in #1164
@ka2048 made their first contribution in #1171
@artificial-aidan made their first contribution in #1147

Full Changelog: v2.10.5…v2.10.6

v2.10.5

2025-07-11

v2.10.5: Middle Management

A maintenance release focused on OpenAPI refinements and middleware fixes, plus console improvements.

What’s Changed

Enhancements 🔧

Fix Claude Code CLI detection for npm global installations by @jlowin in #1106
Fix OpenAPI parameter name collisions with location suffixing by @jlowin in #1107
Add mirrored component support for proxy servers by @jlowin in #1105

Fixes 🐞

Fix OpenAPI deepObject style parameter encoding by @jlowin in #1122
xfail when github token is not set (” or None) by @jlowin in #1123
fix: replace oneOf with anyOf in OpenAPI output schemas by @MagnusS0 in #1119
Fix middleware list result types by @jlowin in #1125
Improve console width for logo by @jlowin in #1126

Docs 📚

Improve transport + integration docs by @jlowin in #1103
Update proxy.mdx by @coldfire-x in #1108

Other Changes 🦾

Update github remote server tests with secret by @jlowin in #1112

New Contributors

@coldfire-x made their first contribution in #1108
@MagnusS0 made their first contribution in #1119

Full Changelog: v2.10.4…v2.10.5

v2.10.4

2025-07-09

v2.10.4: Transport-ation

A quick fix to ensure the CLI accepts “streamable-http” as a valid transport option.

What’s Changed

Fixes 🐞

Ensure the CLI accepts “streamable-http” as a valid transport by @jlowin in #1099

Full Changelog: v2.10.3…v2.10.4

v2.10.3

2025-07-09

v2.10.3: CLI Me a River

A major CLI overhaul featuring a complete refactor from typer to cyclopts, new IDE integrations, and comprehensive OpenAPI improvements.

What’s Changed

New Features 🎉

Refactor CLI from typer to cyclopts and add comprehensive tests by @jlowin in #1062
Add output schema support for OpenAPI tools by @jlowin in #1073

Enhancements 🔧

Add Cursor support via CLI integration by @jlowin in #1052
Add Claude Code install integration by @jlowin in #1053
Generate MCP JSON config output from CLI as new fastmcp install command by @jlowin in #1056
Use isawaitable instead of iscoroutine by @jlowin in #1059
feat: Add --path Option to CLI for HTTP/SSE Route by @davidbk-legit in #1087
Fix concurrent proxy client operations with session isolation by @jlowin in #1083

Fixes 🐞

Refactor Client context management to avoid concurrency issue by @hopeful0 in #1054
Keep json schema $defs on transform by @strawgate in #1066
Ensure fastmcp version copy is plaintext by @jlowin in #1071
Fix single-element list unwrapping in tool content by @jlowin in #1074
Fix max recursion error when pruning OpenAPI definitions by @dimitribarbot in #1092
Fix OpenAPI tool name registration when modified by mcp_component_fn by @jlowin in #1096

Docs 📚

Docs: add example of more concise way to use bearer auth by @neilconway in #1055
Update favicon by @jlowin in #1058
Update environment note by @jlowin in #1075
Add fastmcp version —copy documentation by @jlowin in #1076

Other Changes 🦾

Remove asserts and add documentation following #1054 by @jlowin in #1057
Add —copy flag for fastmcp version by @jlowin in #1063
Fix docstring format for fastmcp.client.Client by @neilconway in #1094

New Contributors

@neilconway made their first contribution in #1055
@davidbk-legit made their first contribution in #1087
@dimitribarbot made their first contribution in #1092

Full Changelog: v2.10.2…v2.10.3

v2.10.2

2025-07-05

v2.10.2: Forward March

The headline feature of this release is the ability to “forward” advanced MCP interactions like logging, progress, and elicitation through proxy servers. If the remote server requests an elicitation, the proxy client will pass that request to the new, “ultimate” client.

What’s Changed

New Features 🎉

Proxy support advanced MCP features by @hopeful0 in #1022

Enhancements 🔧

Re-add splash screen by @jlowin in #1027
Reduce banner padding by @jlowin in #1030
Allow per-server timeouts in MCPConfig by @cegersdoerfer in #1031
Support ‘scp’ claim for OAuth scopes in BearerAuthProvider by @jlowin in #1033
Add path expansion to image/audio/file by @jlowin in #1038
Ensure multi-client configurations use new ProxyClient by @jlowin in #1045

Fixes 🐞

Expose stateless_http kwarg for mcp.run() by @jlowin in #1018
Avoid propagating logs by @jlowin in #1042

Docs 📚

Clean up docs by @jlowin in #1028
Docs: clarify server URL paths for ChatGPT integration by @thap2331 in #1017

Other Changes 🦾

Split giant openapi test file into smaller files by @jlowin in #1034
Add comprehensive OpenAPI 3.0 vs 3.1 compatibility tests by @jlowin in #1035
Update banner and use console.log by @jlowin in #1041

New Contributors

@cegersdoerfer made their first contribution in #1031
@hopeful0 made their first contribution in #1022
@thap2331 made their first contribution in #1017

Full Changelog: v2.10.1…v2.10.2

v2.10.1

2025-07-02

v2.10.1: Revert to Sender

A quick patch to revert the CLI banner that was added in v2.10.0.

What’s Changed

Docs 📚

Update changelog.mdx by @jlowin in #1009
Revert “Add CLI banner” by @jlowin in #1011

Full Changelog: v2.10.0…v2.10.1

v2.10.0

2024-07-01

v2.10.0: Great Spec-tations

FastMCP 2.10 brings full compliance with the 6/18/2025 MCP spec update, introducing elicitation support for dynamic server-client communication and output schemas for structured tool responses. Please note that due to these changes, this release also includes a breaking change to the return signature of client.call_tool().

Elicitation Support

Elicitation allows MCP servers to request additional information from clients during tool execution, enabling more interactive and dynamic server behavior. This opens up new possibilities for tools that need user input or confirmation during execution.

Output Schemas

Tools can now define structured output schemas, ensuring that responses conform to expected formats and making tool integration more predictable and type-safe.

What’s Changed

New Features 🎉

MCP 6/18/25: Add output schema to tools by @jlowin in #901
MCP 6/18/25: Elicitation support by @jlowin in #889

Enhancements 🔧

Update types + tests for SDK changes by @jlowin in #888
MCP 6/18/25: Update auth primitives by @jlowin in #966
Add OpenAPI extensions support to HTTPRoute by @maddymanu in #977
Add title field support to FastMCP components by @jlowin in #982
Support implicit Elicitation acceptance by @jlowin in #983
Support ‘no response’ elicitation requests by @jlowin in #992
Add Support for Configurable Algorithms by @sstene1 in #997

Fixes 🐞

Improve stdio error handling to raise connection failures immediately by @jlowin in #984
Fix type hints for FunctionResource:fn by @CfirTsabari in #986
Update link to OpenAI MCP example by @mossbanay in #985
Fix output schema generation edge case by @jlowin in #995
Refactor array parameter formatting to reduce code duplication by @jlowin in #1007
Fix OpenAPI array parameter explode handling by @jlowin in #1008

Breaking Changes 🛫

MCP 6/18/25: Upgrade to mcp 1.10 by @jlowin in #887

Docs 📚

Update middleware imports and documentation by @jlowin in #999
Update OpenAI docs by @jlowin in #1001
Add CLI banner by @jlowin in #1005

Examples & Contrib 💡

Component Manager by @gorocode in #976

Other Changes 🦾

Minor auth improvements by @jlowin in #967
Add .ccignore for copychat by @jlowin in #1000

New Contributors

@maddymanu made their first contribution in #977
@github0hello made their first contribution in #979
@tommitt made their first contribution in #975
@CfirTsabari made their first contribution in #986
@mossbanay made their first contribution in #985
@sstene1 made their first contribution in #997

Full Changelog: v2.9.2…v2.10.0

v2.9.2

2024-06-26

v2.9.2: Safety Pin

This is a patch release to pin mcp below 1.10, which includes changes related to the 6/18/2025 MCP spec update and could potentially break functionality for some FastMCP users.

What’s Changed

Docs 📚

Fix version badge for messages by @jlowin in #960

Dependencies 📦

Pin mcp dependency by @jlowin in #962

Full Changelog: v2.9.1…v2.9.2

v2.9.1

2024-06-26

v2.9.1: Call Me Maybe

FastMCP 2.9.1 introduces automatic MCP list change notifications, allowing servers to notify clients when tools, resources, or prompts are dynamically updated. This enables more responsive and adaptive MCP integrations.

What’s Changed

New Features 🎉

Add automatic MCP list change notifications and client message handling by @jlowin in #939

Enhancements 🔧

Add debug logging to bearer token authentication by @jlowin in #952

Fixes 🐞

Fix duplicate error logging in exception handlers by @jlowin in #938
Fix parameter location enum handling in OpenAPI parser by @jlowin in #953
Fix external schema reference handling in OpenAPI parser by @jlowin in #954

Docs 📚

Update changelog for 2.9 release by @jlowin in #929
Regenerate API references by @zzstoatzz in #935
Regenerate API references by @zzstoatzz in #947
Regenerate API references by @zzstoatzz in #949

Examples & Contrib 💡

Add create_thread tool to bsky MCP server by @zzstoatzz in #927
Update mount_example.py to work with current fastmcp API by @rajephon in #957

New Contributors

@rajephon made their first contribution in #957

Full Changelog: v2.9.0…v2.9.1

v2.9.0

2024-06-23

v2.9.0: Stuck in the Middleware With You

FastMCP 2.9 introduces two important features that push beyond the basic MCP protocol: MCP Middleware and server-side type conversion.

MCP Middleware

MCP middleware lets you intercept and modify requests and responses at the protocol level, giving you powerful capabilities for logging, authentication, validation, and more. This is particularly useful for building production-ready MCP servers that need sophisticated request handling.

Server-side Type Conversion

This release also introduces server-side type conversion for prompt arguments, ensuring that data is properly formatted before being passed to your functions. This reduces the burden on individual tools and prompts to handle type validation and conversion.

What’s Changed

New Features 🎉

Add File utility for binary data by @gorocode in #843
Consolidate prefix logic into FastMCP methods by @jlowin in #861
Add MCP Middleware by @jlowin in #870
Implement server-side type conversion for prompt arguments by @jlowin in #908

Enhancements 🔧

Fix tool description indentation issue by @zfflxx in #845
Add version parameter to FastMCP constructor by @mkyutani in #842
Update version to not be positional by @jlowin in #848
Add key to component by @jlowin in #869
Add session_id property to Context for data sharing by @jlowin in #881
Fix CORS documentation example by @jlowin in #895

Fixes 🐞

“report_progress missing passing related_request_id causes notifications not working” by @alexsee in #838
Fix JWT issuer validation to support string values per RFC 7519 by @jlowin in #892
Fix BearerAuthProvider audience type annotations by @jlowin in #894

Docs 📚

Add CLAUDE.md development guidelines by @jlowin in #880
Update context docs for session_id property by @jlowin in #882
Add API reference by @zzstoatzz in #893
Fix API ref rendering by @zzstoatzz in #900
Simplify docs nav by @jlowin in #902
Add fastmcp inspect command by @jlowin in #904
Update client docs by @jlowin in #912
Update docs nav by @jlowin in #913
Update integration documentation for Claude Desktop, ChatGPT, and Claude Code by @jlowin in #915
Add http as an alias for streamable http by @jlowin in #917
Clean up parameter documentation by @jlowin in #918
Add middleware examples for timing, logging, rate limiting, and error handling by @jlowin in #919
ControlFlow → FastMCP rename by @jlowin in #922

Examples & Contrib 💡

Add contrib.mcp_mixin support for annotations by @rsp2k in #860
Add ATProto (Bluesky) MCP Server Example by @zzstoatzz in #916
Fix path in atproto example pyproject by @zzstoatzz in #920
Remove uv source in example by @zzstoatzz in #921

New Contributors

@alexsee made their first contribution in #838
@zfflxx made their first contribution in #845
@mkyutani made their first contribution in #842
@gorocode made their first contribution in #843
@rsp2k made their first contribution in #860
@owtaylor made their first contribution in #897
@Jason-CKY made their first contribution in #906

Full Changelog: v2.8.1…v2.9.0

v2.8.1

2024-06-15

v2.8.1: Sound Judgement

2.8.1 introduces audio support, as well as minor fixes and updates for deprecated features.

Audio Support

This release adds support for audio content in MCP tools and resources, expanding FastMCP’s multimedia capabilities beyond text and images.

What’s Changed

New Features 🎉

Add audio support by @jlowin in #833

Enhancements 🔧

Add flag for disabling deprecation warnings by @jlowin in #802
Add examples to Tool Arg Param transformation by @strawgate in #806

Fixes 🐞

Restore .settings access as deprecated by @jlowin in #800
Ensure handling of false http kwargs correctly; removed unused kwarg by @jlowin in #804
Bump mcp 1.9.4 by @jlowin in #835

Docs 📚

Update changelog for 2.8.0 by @jlowin in #794
Update welcome docs by @jlowin in #808
Update headers in docs by @jlowin in #809
Add MCP group to tutorials by @jlowin in #810
Add Community section to documentation by @zzstoatzz in #819
Add 2.8 update by @jlowin in #821
Embed YouTube videos in community showcase by @zzstoatzz in #820

Other Changes 🦾

Ensure http args are passed through by @jlowin in #803
Fix install link in readme by @jlowin in #836

Full Changelog: v2.8.0…v2.8.1

v2.8.0

2024-06-10

v2.8.0: Transform and Roll Out

FastMCP 2.8.0 introduces powerful new ways to customize and control your MCP servers!

Tool Transformation

The highlight of this release is first-class Tool Transformation, a new feature that lets you create enhanced variations of existing tools. You can now easily rename arguments, hide parameters, modify descriptions, and even wrap tools with custom validation or post-processing logic—all without rewriting the original code. This makes it easier than ever to adapt generic tools for specific LLM use cases or to simplify complex APIs. Huge thanks to @strawgate for partnering on this, starting with #591 and #599 and continuing offline.

Component Control

This release also gives you more granular control over which components are exposed to clients. With new tag-based filtering, you can selectively enable or disable tools, resources, and prompts based on tags, perfect for managing different environments or user permissions. Complementing this, every component now supports being programmatically enabled or disabled, offering dynamic control over your server’s capabilities.

Tools-by-Default

Finally, to improve compatibility with a wider range of LLM clients, this release changes the default behavior for OpenAPI integration: all API endpoints are now converted to Tools by default. This is a breaking change but pragmatically necessitated by the fact that the majority of MCP clients available today are, sadly, only compatible with MCP tools. Therefore, this change significantly simplifies the out-of-the-box experience and ensures your entire API is immediately accessible to any tool-using agent.

What’s Changed

New Features 🎉

First-class tool transformation by @jlowin in #745
Support enable/disable for all FastMCP components (tools, prompts, resources, templates) by @jlowin in #781
Add support for tag-based component filtering by @jlowin in #748
Allow tag assignments for OpenAPI by @jlowin in #791

Enhancements 🔧

Create common base class for components by @jlowin in #776
Move components to own file; add resource by @jlowin in #777
Update FastMCP component with eq and repr by @jlowin in #779
Remove open-ended and server-specific settings by @jlowin in #750

Fixes 🐞

Ensure client is only initialized once by @jlowin in #758
Fix field validator for resource by @jlowin in #778
Ensure proxies can overwrite remote tools without falling back to the remote by @jlowin in #782

Breaking Changes 🛫

Treat all openapi routes as tools by @jlowin in #788
Fix issue with global OpenAPI tags by @jlowin in #792

Docs 📚

Minor docs updates by @jlowin in #755
Add 2.7 update by @jlowin in #756
Reduce 2.7 image size by @jlowin in #757
Update updates.mdx by @jlowin in #765
Hide docs sidebar scrollbar by default by @jlowin in #766
Add “stop vibe testing” to tutorials by @jlowin in #767
Add docs links by @jlowin in #768
Fix: updated variable name under Gemini remote client by @yrangana in #769
Revert “Hide docs sidebar scrollbar by default” by @jlowin in #770
Add updates by @jlowin in #773
Add tutorials by @jlowin in #783
Update LLM-friendly docs by @jlowin in #784
Update oauth.mdx by @JeremyCraigMartinez in #787
Add changelog by @jlowin in #789
Add tutorials by @jlowin in #790
Add docs for tag-based filtering by @jlowin in #793

Other Changes 🦾

Create dependabot.yml by @jlowin in #759
Bump astral-sh/setup-uv from 3 to 6 by @dependabot in #760
Add dependencies section to release by @jlowin in #761
Remove extra imports for MCPConfig by @Maanas-Verma in #763
Split out enhancements in release notes by @jlowin in #764

New Contributors

@dependabot made their first contribution in #760
@Maanas-Verma made their first contribution in #763
@JeremyCraigMartinez made their first contribution in #787

Full Changelog: v2.7.1…v2.8.0

v2.7.1

2024-06-08

v2.7.1: The Bearer Necessities

This release primarily contains a fix for parsing string tokens that are provided to FastMCP clients.

New Features 🎉

Respect cache setting, set default to 1 second by @jlowin in #747

Fixes 🐞

Ensure event store is properly typed by @jlowin in #753
Fix passing token string to client auth & add auth to MCPConfig clients by @jlowin in #754

Docs 📚

Docs : fix client to mcp_client in Gemini example by @yrangana in #734
update add tool docstring by @strawgate in #739
Fix contrib link by @richardkmichael in #749

Other Changes 🦾

Switch Pydantic defaults to kwargs by @strawgate in #731
Fix Typo in CLI module by @wfclark5 in #737
chore: fix prompt docstring by @danb27 in #752
Add accept to excluded headers by @jlowin in #751

New Contributors

@wfclark5 made their first contribution in #737
@richardkmichael made their first contribution in #749
@danb27 made their first contribution in #752

Full Changelog: v2.7.0…v2.7.1

v2.7.0

2024-06-05

v2.7.0: Pare Programming

This is primarily a housekeeping release to remove or deprecate cruft that’s accumulated since v1. Primarily, this release refactors FastMCP’s internals in preparation for features planned in the next few major releases. However please note that as a result, this release has some minor breaking changes (which is why it’s 2.7, not 2.6.2, in accordance with repo guidelines) though not to the core user-facing APIs.

Breaking Changes 🛫

decorators return the objects they create, not the decorated function
websockets is an optional dependency
methods on the server for automatically converting functions into tools/resources/prompts have been deprecated in favor of using the decorators directly

New Features 🎉

allow passing flags to servers by @zzstoatzz in #690
replace $ref pointing to `#/components/schemas/` with `#/$ defs/` by @phateffect in #697
Split Tool into Tool and FunctionTool by @jlowin in #700
Use strict basemodel for Prompt; relax from_function deprecation by @jlowin in #701
Formalize resource/functionresource replationship by @jlowin in #702
Formalize template/functiontemplate split by @jlowin in #703
Support flexible @tool decorator call patterns by @jlowin in #706
Ensure deprecation warnings have stacklevel=2 by @jlowin in #710
Allow naked prompt decorator by @jlowin in #711

Fixes 🐞

Updates / Fixes for Tool Content Conversion by @strawgate in #642
Fix pr labeler permissions by @jlowin in #708
remove -n auto by @jlowin in #709
Fix links in README.md by @alainivars in #723

Happily, this release DOES permit the use of “naked” decorators to align with Pythonic practice:

@mcp.tool
def my_tool():
    ...

Full Changelog: v2.6.2…v2.7.0

v2.6.1

2024-06-03

v2.6.1: Blast Auth (second ignition)

This is a patch release to restore py.typed in #686.

Docs 📚

Update readme by @jlowin in #679
Add gemini tutorial by @jlowin in #680
Fix : fix path error to CLI Documentation by @yrangana in #684
Update auth docs by @jlowin in #687

Other Changes 🦾

Remove deprecation notice by @jlowin in #677
Delete server.py by @jlowin in #681
Restore py.typed by @jlowin in #686

New Contributors

@yrangana made their first contribution in #684

Full Changelog: v2.6.0…v2.6.1

v2.6.0

2024-06-02

v2.6.0: Blast Auth

New Features 🎉

Introduce MCP client oauth flow by @jlowin in #478
Support providing tools at init by @jlowin in #647
Simplify code for running servers in processes during tests by @jlowin in #649
Add basic bearer auth for server and client by @jlowin in #650
Support configuring bearer auth from env vars by @jlowin in #652
feat(tool): add support for excluding arguments from tool definition by @deepak-stratforge in #626
Add docs for server + client auth by @jlowin in #655

Fixes 🐞

fix: Support concurrency in FastMcpProxy (and Client) by @Sillocan in #635
Ensure Client.close() cleans up client context appropriately by @jlowin in #643
Update client.mdx: ClientError namespace by @mjkaye in #657

Docs 📚

Make FastMCPTransport support simulated Streamable HTTP Transport (didn’t work) by @jlowin in #645
Document exclude_args by @jlowin in #653
Update welcome by @jlowin in #673
Add Anthropic + Claude desktop integration guides by @jlowin in #674
Minor docs design updates by @jlowin in #676

Other Changes 🦾

Update test typing by @jlowin in #646
Add OpenAI integration docs by @jlowin in #660

New Contributors

@Sillocan made their first contribution in #635
@deepak-stratforge made their first contribution in #626
@mjkaye made their first contribution in #657

Full Changelog: v2.5.2…v2.6.0

v2.5.2

2024-05-29

v2.5.2: Stayin’ Alive

New Features 🎉

Add graceful error handling for unreachable mounted servers by @davenpi in #605
Improve type inference from client transport by @jlowin in #623
Add keep_alive param to reuse subprocess by @jlowin in #624

Fixes 🐞

Fix handling tools without descriptions by @jlowin in #610
Don’t print env vars to console when format is wrong by @jlowin in #615
Ensure behavior-affecting headers are excluded when forwarding proxies/openapi by @jlowin in #620

Docs 📚

Add notes about uv and claude desktop by @jlowin in #597

Other Changes 🦾

add init_timeout for mcp client by @jfouret in #607
Add init_timeout for mcp client (incl settings) by @jlowin in #609
Support for uppercase letters at the log level by @ksawaray in #625

New Contributors

@jfouret made their first contribution in #607
@ksawaray made their first contribution in #625

Full Changelog: v2.5.1…v2.5.2

v2.5.1

2024-05-24

v2.5.1: Route Awakening (Part 2)

Fixes 🐞

Ensure content-length is always stripped from client headers by @jlowin in #589

Docs 📚

Fix redundant section of docs by @jlowin in #583

Full Changelog: v2.5.0…v2.5.1

v2.5.0

2024-05-24

v2.5.0: Route Awakening

This release introduces completely new tools for generating and customizing MCP servers from OpenAPI specs and FastAPI apps, including popular requests like mechanisms for determining what routes map to what MCP components; renaming routes; and customizing the generated MCP components.

New Features 🎉

Add FastMCP 1.0 server support for in-memory Client / Testing by @jlowin in #539
Minor addition: add transport to stdio server in mcpconfig, with default by @jlowin in #555
Raise an error if a Client is created with no servers in config by @jlowin in #554
Expose model preferences in Context.sample for flexible model selection. by @davenpi in #542
Ensure custom routes are respected by @jlowin in #558
Add client method to send cancellation notifications by @davenpi in #563
Enhance route map logic for include/exclude OpenAPI routes by @jlowin in #564
Add tag-based route maps by @jlowin in #565
Add advanced control of openAPI route creation by @jlowin in #566
Make error masking configurable by @jlowin in #550
Ensure client headers are passed through to remote servers by @jlowin in #575
Use lowercase name for headers when comparing by @jlowin in #576
Permit more flexible name generation for OpenAPI servers by @jlowin in #578
Ensure that tools/templates/prompts are compatible with callable objects by @jlowin in #579

Docs 📚

Add version badge for prefix formats by @jlowin in #537
Add versioning note to docs by @jlowin in #551
Bump 2.3.6 references to 2.4.0 by @jlowin in #567

Full Changelog: v2.4.0…v2.5.0

v2.4.0

2024-05-21

v2.4.0: Config and Conquer

Note: this release includes a backwards-incompatible change to how resources are prefixed when mounted in composed servers. However, it is only backwards-incompatible if users were running tests or manually loading resources by prefixed key; LLMs should not have any issue discovering the new route. See Resource Prefix Formats for more.

New Features 🎉

Allow * Methods and all routes as tools shortcuts by @jlowin in #520
Improved support for config dicts by @jlowin in #522
Support creating clients from MCP config dicts, including multi-server clients by @jlowin in #527
Make resource prefix format configurable by @jlowin in #534

Fixes 🐞

Avoid hanging on initializing server session by @jlowin in #523

Breaking Changes 🛫

Remove customizable separators; improve resource separator by @jlowin in #526

Docs 📚

Improve client documentation by @jlowin in #517

Other Changes 🦾

Ensure openapi path params are handled properly by @jlowin in #519
better error when missing lifespan by @zzstoatzz in #521

Full Changelog: v2.3.5…v2.4.0

v2.3.5

2024-05-20

v2.3.5: Making Progress

New Features 🎉

support messages in progress notifications by @rickygenhealth in #471
feat: Add middleware option in server.run by @Maxi91f in #475
Add lifespan property to app by @jlowin in #483
Update fastmcp run to work with remote servers by @jlowin in #491
Add FastMCP.as_proxy() by @jlowin in #490
Infer sse transport from urls containing /sse by @jlowin in #512
Add progress handler to client by @jlowin in #513
Store the initialize result on the client by @jlowin in #509

Fixes 🐞

Remove patch and use upstream SSEServerTransport by @jlowin in #425

Docs 📚

Update transport docs by @jlowin in #458
update proxy docs + example by @zzstoatzz in #460
doc(asgi): Change custom route example to PlainTextResponse by @mcw0933 in #477
Store FastMCP instance on app.state.fastmcp_server by @jlowin in #489
Improve AGENTS.md overview by @jlowin in #492
Update release numbers for anticipated version by @jlowin in #516

Other Changes 🦾

run tests on all PRs by @jlowin in #468
add null check by @zzstoatzz in #473
strict typing for server.py by @zzstoatzz in #476
Doc(quickstart): Fix import statements by @mai-nakagawa in #479
Add labeler by @jlowin in #484
Fix flaky timeout test by increasing timeout (#474) by @davenpi in #486
Skipping test_permission_error if runner is root. by @ZiadAmerr in #502
allow passing full uvicorn config by @zzstoatzz in #504
Skip timeout tests on windows by @jlowin in #514

New Contributors

@rickygenhealth made their first contribution in #471
@Maxi91f made their first contribution in #475
@mcw0933 made their first contribution in #477
@mai-nakagawa made their first contribution in #479
@ZiadAmerr made their first contribution in #502

Full Changelog: v2.3.4…v2.3.5

v2.3.4

2024-05-15

v2.3.4: Error Today, Gone Tomorrow

New Features 🎉

logging stack trace for easier debugging by @jbkoh in #413
add missing StreamableHttpTransport in client exports by @yihuang in #408
Improve error handling for tools and resources by @jlowin in #434
feat: add support for removing tools from server by @davenpi in #437
Prune titles from JSONSchemas by @jlowin in #449
Declare toolsChanged capability for stdio server. by @davenpi in #450
Improve handling of exceptiongroups when raised in clients by @jlowin in #452
Add timeout support to client by @jlowin in #455

Fixes 🐞

Pin to mcp 1.8.1 to resolve callback deadlocks with SHTTP by @jlowin in #427
Add reprs for OpenAPI objects by @jlowin in #447
Ensure openapi defs for structured objects are loaded properly by @jlowin in #448
Ensure tests run against correct python version by @jlowin in #454
Ensure result is only returned if a new key was found by @jlowin in #456

Docs 📚

Add documentation for tool removal by @jlowin in #440

Other Changes 🦾

Deprecate passing settings to the FastMCP instance by @jlowin in #424
Add path prefix to test by @jlowin in #432

New Contributors

@jbkoh made their first contribution in #413
@davenpi made their first contribution in #437

Full Changelog: v2.3.3…v2.3.4

v2.3.3

2024-05-10

v2.3.3: SSE you later

This is a hotfix for a bug introduced in 2.3.2 that broke SSE servers

Fixes 🐞

Fix bug that sets message path and sse path to same value by @jlowin in #405

Docs 📚

Update composition docs by @jlowin in #403

Other Changes 🦾

Add test for no prefix when importing by @jlowin in #404

Full Changelog: v2.3.2…v2.3.3

v2.3.2

2024-05-10

v2.3.2: Stuck in the Middleware With You

New Features 🎉

Allow users to pass middleware to starlette app constructors by @jlowin in #398
Deprecate transport-specific methods on FastMCP server by @jlowin in #401

Docs 📚

Update CLI docs by @jlowin in #402

Other Changes 🦾

Adding 23 tests for CLI by @didier-durand in #394

Full Changelog: v2.3.1…v2.3.2

v2.3.1

2024-05-09

v2.3.1: For Good-nests Sake

This release primarily patches a long-standing bug with nested ASGI SSE servers.

Fixes 🐞

Fix tool result serialization when the tool returns a list by @strawgate in #379
Ensure FastMCP handles nested SSE and SHTTP apps properly in ASGI frameworks by @jlowin in #390

Docs 📚

Update transport docs by @jlowin in #377
Add llms.txt to docs by @jlowin in #384
Fixing various text typos by @didier-durand in #385

Other Changes 🦾

Adding a few tests to Image type by @didier-durand in #387
Adding tests for TimedCache by @didier-durand in #388

New Contributors

@didier-durand made their first contribution in #385

Full Changelog: v2.3.0…v2.3.1

v2.3.0

2024-05-08

v2.3.0: Stream Me Up, Scotty

New Features 🎉

Add streaming support for HTTP transport by @jlowin in #365
Support streaming HTTP transport in clients by @jlowin in #366
Add streaming support to CLI by @jlowin in #367

Fixes 🐞

Fix streaming transport initialization by @jlowin in #368

Docs 📚

Update transport documentation for streaming support by @jlowin in #369

Full Changelog: v2.2.10…v2.3.0

v2.2.10

2024-05-06

v2.2.10: That’s JSON Bourne

Fixes 🐞

Disable automatic JSON parsing of tool args by @jlowin in #341
Fix prompt test by @jlowin in #342

Other Changes 🦾

Update docs.json by @jlowin in #338
Add test coverage + tests on 4 examples by @alainivars in #306

New Contributors

@alainivars made their first contribution in #306

Full Changelog: v2.2.9…v2.2.10

v2.2.9

2024-05-06

v2.2.9: Str-ing the Pot (Hotfix)

This release is a hotfix for the issue detailed in #330

Fixes 🐞

Prevent invalid resource URIs by @jlowin in #336
Coerce numbers to str by @jlowin in #337

Docs 📚

Add client badge by @jlowin in #327
Update bug.yml by @jlowin in #328

Other Changes 🦾

Update quickstart.mdx example to include import by @discdiver in #329

New Contributors

@discdiver made their first contribution in #329

Full Changelog: v2.2.8…v2.2.9

v2.2.8

2024-05-05

v2.2.8: Parse and Recreation

New Features 🎉

Replace custom parsing with TypeAdapter by @jlowin in #314
Handle *args/**kwargs appropriately for various components by @jlowin in #317
Add timeout-graceful-shutdown as a default config for SSE app by @jlowin in #323
Ensure prompts return descriptions by @jlowin in #325

Fixes 🐞

Ensure that tool serialization has a graceful fallback by @jlowin in #310

Docs 📚

Update docs for clarity by @jlowin in #312

Other Changes 🦾

Remove is_async attribute by @jlowin in #315
Dry out retrieving context kwarg by @jlowin in #316

Full Changelog: v2.2.7…v2.2.8

v2.2.7

2024-05-03

v2.2.7: You Auth to Know Better

New Features 🎉

use pydantic_core.to_json by @jlowin in #290
Ensure openapi descriptions are included in tool details by @jlowin in #293
Bump mcp to 1.7.1 by @jlowin in #298
Add support for tool annotations by @jlowin in #299
Add auth support by @jlowin in #300
Add low-level methods to client by @jlowin in #301
Add method for retrieving current starlette request to FastMCP context by @jlowin in #302
get_starlette_request → get_http_request by @jlowin in #303
Support custom Serializer for Tools by @strawgate in #308
Support proxy mount by @jlowin in #309

Other Changes 🦾

Improve context injection type checks by @jlowin in #291
add readme to smarthome example by @zzstoatzz in #294

Full Changelog: v2.2.6…v2.2.7

v2.2.6

2024-04-30

v2.2.6: The REST is History

New Features 🎉

Added feature : Load MCP server using config by @sandipan1 in #260
small typing fixes by @zzstoatzz in #237
Expose configurable timeout for OpenAPI by @jlowin in #279
Lower websockets pin for compatibility by @jlowin in #286
Improve OpenAPI param handling by @jlowin in #287

Fixes 🐞

Ensure openapi tool responses are properly converted by @jlowin in #283
Fix OpenAPI examples by @jlowin in #285
Fix client docs for advanced features, add tests for logging by @jlowin in #284

Other Changes 🦾

add testing doc by @jlowin in #264
#267 Fix openapi template resource to support multiple path parameters by @jeger-at in #278

New Contributors

@sandipan1 made their first contribution in #260
@jeger-at made their first contribution in #278

Full Changelog: v2.2.5…v2.2.6

v2.2.5

2024-04-26

v2.2.5: Context Switching

New Features 🎉

Add tests for tool return types; improve serialization behavior by @jlowin in #262
Support context injection in resources, templates, and prompts (like tools) by @jlowin in #263

Docs 📚

Update wildcards to 2.2.4 by @jlowin in #257
Update note in templates docs by @jlowin in #258
Significant documentation and test expansion for tool input types by @jlowin in #261

Full Changelog: v2.2.4…v2.2.5

v2.2.4

2024-04-25

v2.2.4: The Wild Side, Actually

The wildcard URI templates exposed in v2.2.3 were blocked by a server-level check which is removed in this release.

New Features 🎉

Allow customization of inspector proxy port, ui port, and version by @jlowin in #253

Fixes 🐞

fix: unintended type convert by @cutekibry in #252
Ensure openapi resources return valid responses by @jlowin in #254
Ensure servers expose template wildcards by @jlowin in #256

Docs 📚

Update README.md Grammar error by @TechWithTy in #249

Other Changes 🦾

Add resource template tests by @jlowin in #255

New Contributors

@TechWithTy made their first contribution in #249
@cutekibry made their first contribution in #252

Full Changelog: v2.2.3…v2.2.4

v2.2.3

2024-04-25

v2.2.3: The Wild Side

New Features 🎉

Add wildcard params for resource templates by @jlowin in #246

Docs 📚

Indicate that Image class is for returns by @jlowin in #242
Update mermaid diagram by @jlowin in #243

Other Changes 🦾

update version badges by @jlowin in #248

Full Changelog: v2.2.2…v2.2.3

v2.2.2

2024-04-24

v2.2.2: Prompt and Circumstance

New Features 🎉

Add prompt support by @jlowin in #235

Fixes 🐞

Ensure that resource templates are properly exposed by @jlowin in #238

Docs 📚

Update docs for prompts by @jlowin in #236

Other Changes 🦾

Add prompt tests by @jlowin in #239

Full Changelog: v2.2.1…v2.2.2

v2.2.1

2024-04-23

v2.2.1: Template for Success

New Features 🎉

Add resource templates by @jlowin in #230

Fixes 🐞

Ensure that resource templates are properly exposed by @jlowin in #231

Docs 📚

Update docs for resource templates by @jlowin in #232

Other Changes 🦾

Add resource template tests by @jlowin in #233

Full Changelog: v2.2.0…v2.2.1

v2.2.0

2024-04-22

v2.2.0: Compose Yourself

New Features 🎉

Add support for mounting FastMCP servers by @jlowin in #175
Add support for duplicate behavior == ignore by @jlowin in #169

Breaking Changes 🛫

Refactor MCP composition by @jlowin in #176

Docs 📚

Improve integration documentation by @jlowin in #184
Improve documentation by @jlowin in #185

Other Changes 🦾

Add transport kwargs for mcp.run() and fastmcp run by @jlowin in #161
Allow resource templates to have optional / excluded arguments by @jlowin in #164
Update resources.mdx by @jlowin in #165

New Contributors

@kongqi404 made their first contribution in #181

Full Changelog: v2.1.2…v2.2.0

v2.1.2

2024-04-14

v2.1.2: Copy That, Good Buddy

The main improvement in this release is a fix that allows FastAPI / OpenAPI-generated servers to be mounted as sub-servers.

Fixes 🐞

Ensure objects are copied properly and test mounting fastapi by @jlowin in #153

Docs 📚

Fix broken links in docs by @jlowin in #154

Other Changes 🦾

Update README.md by @jlowin in #149
Only apply log config to FastMCP loggers by @jlowin in #155
Update pyproject.toml by @jlowin in #156

Full Changelog: v2.1.1…v2.1.2

v2.1.1

2024-04-14

v2.1.1: Doc Holiday

FastMCP’s docs are now available at gofastmcp.com.

Docs 📚

Add docs by @jlowin in #136
Add docs link to readme by @jlowin in #137
Minor docs updates by @jlowin in #138

Fixes 🐞

fix branch name in example by @zzstoatzz in #140

Other Changes 🦾

smart home example by @zzstoatzz in #115
Remove mac os tests by @jlowin in #142
Expand support for various method interactions by @jlowin in #143
Update docs and add_resource_fn by @jlowin in #144
Update description by @jlowin in #145
Support openapi 3.0 and 3.1 by @jlowin in #147

Full Changelog: v2.1.0…v2.1.1

v2.1.0

2024-04-13

v2.1.0: Tag, You’re It

The primary motivation for this release is the fix in #128 for Claude desktop compatibility, but the primary new feature of this release is per-object tags. Currently these are for bookkeeping only but will become useful in future releases.

New Features 🎉

Add tags for all core MCP objects by @jlowin in #121
Ensure that openapi tags are transferred to MCP objects by @jlowin in #124

Fixes 🐞

Change default mounted tool separator from / to _ by @jlowin in #128
Enter mounted app lifespans by @jlowin in #129
Fix CLI that called mcp instead of fastmcp by @jlowin in #128

Breaking Changes 🛫

Changed configuration for duplicate resources/tools/prompts by @jlowin in #121
Improve client return types by @jlowin in #123

Other Changes 🦾

Add tests for tags in server decorators by @jlowin in #122
Clean up server tests by @jlowin in #125

Full Changelog: v2.0.0…v2.1.0

v2.0.0

2024-04-11

v2.0.0: Second to None

New Features 🎉

Support mounting FastMCP instances as sub-MCPs by @jlowin in #99
Add in-memory client for calling FastMCP servers (and tests) by @jlowin in #100
Add MCP proxy server by @jlowin in #105
Update FastMCP for upstream changes by @jlowin in #107
Generate FastMCP servers from OpenAPI specs and FastAPI by @jlowin in #110
Reorganize all client / transports by @jlowin in #111
Add sampling and roots by @jlowin in #117

Fixes 🐞

Fix bug with tools that return lists by @jlowin in #116

Other Changes 🦾

Add back FastMCP CLI by @jlowin in #108
Update Readme for v2 by @jlowin in #112
fix deprecation warnings by @zzstoatzz in #113
Readme by @jlowin in #118
FastMCP 2.0 by @jlowin in #119

Full Changelog: v1.0…v2.0.0

v1.0

2024-04-11

v1.0: It’s Official

This release commemorates FastMCP 1.0, which is included in the official Model Context Protocol SDK:

from mcp.server.fastmcp import FastMCP

To the best of my knowledge, v1 is identical to the upstream version included with mcp.

Docs 📚

Update readme to redirect to the official SDK by @jlowin in #79

Other Changes 🦾

fix: use Mount instead of Route for SSE message handling by @samihamine in #77

New Contributors

@samihamine made their first contribution in #77

Full Changelog: v0.4.1…v1.0

v0.4.1

2024-12-09

v0.4.1: String Theory

Fixes 🐞

fix: handle strings containing numbers correctly by @sd2k in #63

Docs 📚

patch: Update pyproject.toml license by @leonkozlowski in #67

Other Changes 🦾

Avoid new try_eval_type unavailable with older pydantic by @jurasofish in #57
Decorator typing by @jurasofish in #56

New Contributors

@leonkozlowski made their first contribution in #67

Full Changelog: v0.4.0…v0.4.1

v0.4.0

2024-12-05

v0.4.0: Nice to MIT You

This is a relatively small release in terms of features, but the version is bumped to 0.4 to reflect that the code is being relicensed from Apache 2.0 to MIT. This is to facilitate FastMCP’s inclusion in the official MCP SDK.

New Features 🎉

Add pyright + tests by @jlowin in #52
add pgvector memory example by @zzstoatzz in #49

Fixes 🐞

fix: use stderr for logging by @sd2k in #51

Docs 📚

Update ai-labeler.yml by @jlowin in #48
Relicense from Apache 2.0 to MIT by @jlowin in #54

Other Changes 🦾

fix warning and flake by @zzstoatzz in #47

New Contributors

@sd2k made their first contribution in #51

Full Changelog: v0.3.5…v0.4.0

v0.3.5

2024-12-03

v0.3.5: Windows of Opportunity

This release is highlighted by the ability to handle complex JSON objects as MCP inputs and improved Windows compatibility.

New Features 🎉

Set up multiple os tests by @jlowin in #44
Changes to accomodate windows users. by @justjoehere in #42
Handle complex inputs by @jurasofish in #31

Docs 📚

Make AI labeler more conservative by @jlowin in #46

Other Changes 🦾

Additional Windows Fixes for Dev running and for importing modules in a server by @justjoehere in #43

New Contributors

@justjoehere made their first contribution in #42
@jurasofish made their first contribution in #31

Full Changelog: v0.3.4…v0.3.5

v0.3.4

2024-12-02

v0.3.4: URL’s Well That Ends Well

Fixes 🐞

Handle missing config file when installing by @jlowin in #37
Remove BaseURL reference and use AnyURL by @jlowin in #40

Full Changelog: v0.3.3…v0.3.4

v0.3.3

2024-12-02

v0.3.3: Dependence Day

New Features 🎉

Surge example by @zzstoatzz in #29
Support Python dependencies in Server by @jlowin in #34

Docs 📚

add Contributing section to README by @zzstoatzz in #32

Full Changelog: v0.3.2…v0.3.3

v0.3.2

Green with ENVy

v0.3.2: Green with ENVy

New Features 🎉

Support env vars when installing by @jlowin in #27

Docs 📚

Remove top level env var by @jlowin in #28

Full Changelog: v0.3.1…v0.3.2

v0.3.1

2024-12-01

v0.3.1

New Features 🎉

Update README.md by @jlowin in #23
add rich handler and dotenv loading for settings by @zzstoatzz in #22
print exception when server can’t start by @jlowin in #25

Docs 📚

Update README.md by @jlowin in #24

Other Changes 🦾

Remove log by @jlowin in #26

Full Changelog: v0.3.0…v0.3.1

v0.3.0

2024-12-01

v0.3.0: Prompt and Circumstance

New Features 🎉

Update README by @jlowin in #3
Make log levels strings by @jlowin in #4
Make content method a function by @jlowin in #5
Add template support by @jlowin in #6
Refactor resources module by @jlowin in #7
Clean up cli imports by @jlowin in #8
Prepare to list templates by @jlowin in #11
Move image to separate module by @jlowin in #9
Add support for request context, progress, logging, etc. by @jlowin in #12
Add context tests and better runtime loads by @jlowin in #13
Refactor tools + resourcemanager by @jlowin in #14
func → fn everywhere by @jlowin in #15
Add support for prompts by @jlowin in #16
Create LICENSE by @jlowin in #18
Update cli file spec by @jlowin in #19
Update readmeUpdate README by @jlowin in #20
Use hatchling for version by @jlowin in #21

Other Changes 🦾

Add echo server by @jlowin in #1
Add github workflows by @jlowin in #2
typing updates by @zzstoatzz in #17

New Contributors

@jlowin made their first contribution in #1
@zzstoatzz made their first contribution in #17

Full Changelog: v0.2.0…v0.3.0

v0.2.0

2024-11-30

v0.2.0

Full Changelog: v0.1.0…v0.2.0

v0.1.0

2024-11-30

v0.1.0

The very first release of FastMCP! 🎉Full Changelog: Initial commits

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