URL: https://gofastmcp.com/updates
Title: FastMCP Updates - FastMCP

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FastMCP 3.4.1
Releases
June 5, 2026
FastMCP v3.4.1: Floor It
A security patch. FastMCP now floors Starlette at
>=1.0.1
, so installs can no longer resolve to a version affected by CVE-2026-48710 — previously the dependency was only constrained transitively through
mcp
. OAuthProxy also logs refresh-token cache misses instead of failing silently.
Read the release notes
​
FastMCP 3.4.0
Releases
June 2, 2026
FastMCP v3.4.0: Remote Control
The remote release.
fastmcp-remote
is a standalone bridge that connects stdio-only MCP hosts to servers hosted over HTTP, with OAuth enabled automatically for HTTPS. The proxy layer underneath it is hardened so bridges fail loudly on a missing or misconfigured upstream, and FastMCP-issued tokens can now outlive short-lived upstream tokens to survive long idle periods.
🌉
fastmcp-remote
—
uvx fastmcp-remote https://example.com/mcp
bridges a remote server back to a stdio-only host.
🔌
Bridges fail loudly
— proxies forward
initialize
upstream, so a missing backend or wrong URL fails the handshake instead of returning an empty-but-connected proxy.
🔐
Longer-lived tokens
—
fastmcp_access_token_expiry_seconds
decouples the client-facing token lifetime from a short upstream
expires_in
.
⚠️
Returnable tool errors
—
ToolResult(..., is_error=True)
hands back rich errors the model can act on instead of only raising.
Read the release notes
​
FastMCP 3.3.1
Releases
May 15, 2026
FastMCP v3.3.1: Loop There It Is
Hotfix for the 3.3 packaging split: standalone component imports like
from fastmcp.tools import tool
no longer pull in the server stack or trip a circular import. Component-level auth and task primitives moved to lightweight utility modules, with the old import paths preserved as compatibility re-exports.
Read the release notes
​
FastMCP 3.3.0
Releases
May 15, 2026
FastMCP v3.3.0: Slim Reaper
The
fastmcp-slim
release. A dependency-light distribution that ships FastMCP’s client and transport layer without Starlette, Uvicorn, or the server stack — the import namespace is unchanged. It also closes out a backlog of OAuth proxy hardening, MCP-compliant OTEL instrumentation, and auth additions.
🪶
fastmcp-slim
— install the client without the server footprint for CI, agents, and library dependencies.
🔐
OAuth proxy hardening
— silent-consent AS-in-the-middle guard, dot-segment redirect rejection, and per-token response cache partitioning.
🔑
Auth additions
—
AzureB2CProvider
user flows and a public
update_scopes()
API on
OAuthProxy
.
🧵
Thread affinity
—
@mcp.tool(run_in_thread=False)
for tools bound to a specific thread.
Read the release notes
​
FastMCP 3.2.4
Releases
April 14, 2026
FastMCP v3.2.4: Patch Me If You Can
A grab bag of fixes and hardening. Background tasks are now scoped to the authorization context instead of the MCP session — a breaking change for anyone relying on session-scoped semantics — and parameter descriptions are extracted from docstrings automatically.
🔐
Security
—
FileUpload
validates decoded base64 size, the proxy stops forwarding inbound headers to unrelated servers, and AuthKit binds token audience per RFC 8707.
🔑
Keycloak
— new OAuth provider for enterprise auth and local dev.
Read the release notes
​
FastMCP 3.2.3
Releases
April 9, 2026
FastMCP v3.2.3: Redis or Not
Pins
fakeredis<2.35.0
in the
tasks
extra: a 2.35.0 rename broke pydocket’s
memory://
backend and made
fastmcp[tasks]
installs fail at startup with an
ImportError
.
Read the release notes
​
FastMCP 3.2.2
Releases
April 9, 2026
FastMCP v3.2.2: Audience Appreciation
Fixes the Azure audience regression from 3.2.1 — both the bare client ID GUID and a custom
identifier_uri
are now accepted as the token audience.
Read the release notes
​
FastMCP 3.2.1
Releases
April 8, 2026
FastMCP v3.2.1: Audience Participation
A patch focused on auth-provider audience validation: Cognito validates on
client_id
, Azure honors
identifier_uri
, and consent cookies are LRU-capped to avoid header overflow. Also fixes OpenAPI 3.0
nullable
fields leaking into tool input schemas and server-variable substitution in base URLs.
Read the release notes
​
FastMCP 3.2.0
Releases
March 30, 2026
FastMCP v3.2.0: Show Don't Tool
The Apps release. Your tools can return interactive UIs — charts, dashboards, forms, maps — rendered right inside the conversation.
🎨
FastMCPApp
— separate the tools the LLM sees (
@app.ui()
) from the backend tools the UI calls (
@app.tool()
), built on Prefab.
🧩
Built-in providers
— FileUpload, Approval, Choice, FormInput, and GenerativeUI.
🖥️
Dev server
—
fastmcp dev apps
previews app tools in the browser with an MCP message inspector.
🔒
Security pass
— SSRF/path-traversal prevention, JWT algorithm restrictions, OAuth scope enforcement, and CSRF fixes.
Read the release notes
​
FastMCP 3.1.1
Releases
March 14, 2026
FastMCP v3.1.1: 'Tis But a Patch
Pins
pydantic-monty<0.0.8
to fix a breaking change in Monty that affects code mode.
Read the release notes
​
FastMCP 3.1.0
Releases
March 3, 2026
FastMCP v3.1.0: Code to Joy
The Code Mode release. Instead of loading the entire tool catalog into context,
CodeMode
gives LLMs meta-tools: search for relevant tools on demand, inspect their schemas, then write Python that chains
call_tool()
calls in a sandbox. Also ships search transforms, early Prefab Apps integration,
MultiAuth
for composing multiple token verification sources, and PropelAuth support.
Read the release notes
​
FastMCP 3.0.2
Releases
February 22, 2026
FastMCP v3.0.2: Threecovery Mode II
Two community-contributed fixes: auth headers from MCP transport no longer leak through to downstream OpenAPI APIs, and background task workers now correctly receive the originating request ID. Plus a new docs example for context-aware tool factories.
Read the release notes
​
FastMCP 3.0.1
Releases
February 20, 2026
FastMCP v3.0.1: Three-covery Mode
First patch after 3.0 — mostly smoothing out rough edges discovered in the wild. The big ones: middleware state that wasn’t surviving the trip to tool handlers now does,
Tool.from_tool()
accepts callables again, OpenAPI schemas with circular references no longer crash discovery, and decorator overloads now return the correct types in function mode.
🔐
OIDC
verify_id_token
— New option for providers that issue opaque access tokens but standard JWT id_tokens. Verifies identity via the id_token while using the access_token for upstream API calls.
🐞
11 bug fixes
— State serialization, future annotations with
Context
/
Depends
, OpenAI handler deprecation warnings, type checker compatibility, and more.
Read the release notes
​
FastMCP 3.0.0
Releases
February 18, 2026
FastMCP v3.0.0: Three at Last
FastMCP 3.0 is stable. Two betas, two release candidates, 21 new contributors, and more than 100,000 pre-release installs later — the architecture held up, the upgrade path was smooth, and we’re shipping it.
The surface API is largely unchanged —
@mcp.tool()
still works exactly as before. What changed is everything underneath: a provider/transform architecture that makes FastMCP extensible, observable, and composable in ways v2 couldn’t support.
🔌
Build servers from anything
—
FileSystemProvider
,
OpenAPIProvider
,
ProxyProvider
,
SkillsProvider
, and composable transforms that rename, namespace, filter, version, and secure components as they flow to clients.
🔐
Ship to production
— Component versioning, granular authorization with async auth checks, CIMD, Static Client Registration, Azure OBO, OpenTelemetry tracing, and background tasks with distributed Redis notification.
💾
Adapt per session
— Session state persists across requests, and
ctx.enable_components()
/
ctx.disable_components()
let servers adapt dynamically per client.
⚡
Develop faster
—
--reload
, standalone decorators, automatic threadpool dispatch, tool timeouts, pagination, and concurrent tool execution.
🖥️
CLI
—
fastmcp list
,
fastmcp call
,
fastmcp discover
,
fastmcp generate-cli
, and
fastmcp install
for Claude Desktop, Cursor, and Goose.
Read the release notes
​
FastMCP 3.0.0rc1
Releases
February 12, 2026
FastMCP v3.0.0rc1: RC-ing is Believing
FastMCP 3 RC1 means we believe the API is stable. Beta 2 drew a wave of real-world adoption — production deployments, migration reports, integration testing — and the feedback overwhelmingly confirmed that the architecture works. This release closes gaps that surfaced under load: auth flows that needed to be async, background tasks that needed reliable notification delivery, and APIs still carrying beta-era naming. If nothing unexpected surfaces, this is what 3.0.0 looks like.
🚨
Breaking Changes
— The
ui=
parameter is now
app=
with a unified
AppConfig
class, and 16
FastMCP()
constructor kwargs have been removed after months of deprecation warnings.
🔐
Auth Improvements
— Async
auth=
checks, Static Client Registration for servers without DCR, and declarative Azure OBO flows via dependency injection.
⚡
Concurrent Sampling
—
context.sample()
can now execute multiple tool calls in parallel with
tool_concurrency=0
.
📡
Background Task Notifications
— A distributed Redis queue replaces polling for progress updates and elicitation relay.
✅
OpenAPI Output Validation
—
validate_output=False
disables strict schema checking for imperfect backend APIs.
Read the release notes
​
FastMCP 3.0.0b2
Releases
February 7, 2026
FastMCP v3.0.0b2: 2 Fast 2 Beta
Beta 2 reflects the huge number of people that kicked the tires on Beta 1. Seven new contributors landed changes, and early migration reports went smoother than expected. Most of Beta 2 is refinement — fixing what people found, filling gaps from real usage, hardening edges — but a few new features landed along the way.
🖥️
Client CLI
—
fastmcp list
,
fastmcp call
,
fastmcp discover
, and
fastmcp generate-cli
turn any MCP server into something you can poke at from a terminal.
🔐
CIMD
(Client ID Metadata Documents) adds an alternative to Dynamic Client Registration for OAuth.
📱
MCP Apps
— Spec-level compliance for the MCP Apps extension with
ui://
resource scheme and typed UI metadata.
⏳
Background Task Context
—
Context
now works transparently in Docket workers with Redis-based coordination.
🛡️
ResponseLimitingMiddleware
caps tool response sizes with UTF-8-safe truncation.
🪿
Goose Integration
—
fastmcp install goose
for one-command server installation into Goose.
Read the release notes
​
FastMCP 3.0.0b1
Releases
January 20, 2026
FastMCP 3.0.0b1: This Beta Work
FastMCP 3.0 rebuilds the framework around three primitives: components, providers, and transforms. Providers source components dynamically—from decorators, filesystems, OpenAPI specs, remote servers, or anywhere else. Transforms modify components as they flow to clients. The features that required specialized subsystems in v2 now compose naturally from these building blocks.
🔌
Provider Architecture
unifies how components are sourced with
FileSystemProvider
,
SkillsProvider
,
OpenAPIProvider
, and
ProxyProvider
.
🔄
Transforms
add middleware for components—namespace, rename, filter by version, control visibility.
📋
Component Versioning
lets you register multiple versions of the same tool with automatic highest-version selection.
💾
Session-Scoped State
persists across requests, with per-session visibility control.
⚡
DX Improvements
include
--reload
for development, automatic threadpool dispatch, tool timeouts, pagination, and OpenTelemetry tracing.
Read the release notes
​
FastMCP 2.14.7
Releases
April 13, 2026
FastMCP 2.14.7: Fake It Till You Break It
A 2.x backport of the fakeredis pin: fakeredis 2.35.0 renamed a connection class that pydocket’s
memory://
backend relied on, crashing
fastmcp[tasks]
installs at startup. Caps
fakeredis<2.35.0
on the 2.x line.
Read the release notes
​
FastMCP 2.14.6
Releases
March 27, 2026
FastMCP 2.14.6: $Ref Dead Redemption
v2.14.4 backported
dereference_refs()
but never wired it into the tool schema pipeline —
$ref
and
$defs
were still sent to MCP clients. Now fixed: schemas are fully inlined before reaching clients.
Read the release notes
​
FastMCP 2.14.5
Releases
February 3, 2026
FastMCP 2.14.5: Sealed Docket
Fixes a memory leak in the memory:// docket broker where cancelled tasks accumulated instead of being cleaned up. Bumps pydocket to ≥0.17.2.
Read the release notes
​
FastMCP 2.14.4
Releases
January 22, 2026
FastMCP 2.14.4: Package Deal
Fixes a fresh install bug where the packaging library was missing as a direct dependency, plus backports $ref dereferencing in tool schemas and a task capabilities location fix.
Read the release notes
​
FastMCP 2.14.3
Releases
January 12, 2026
FastMCP 2.14.3: Time After Timeout
Sometimes five seconds just isn’t enough. This release fixes an HTTP transport bug that was cutting connections short, along with OAuth and Redis fixes, better ASGI support, and CLI update notifications so you never miss a beat.
⏱️
HTTP transport timeout fix
restores MCP’s 30-second default connect timeout, which was incorrectly defaulting to 5 seconds.
🔧
Infrastructure fixes
including OAuth token storage TTL, Redis key prefixing for ACL isolation, and ContextVar propagation for ASGI-mounted servers with background tasks.
Read the release notes
​
FastMCP 2.14.2
Releases
December 31, 2025
FastMCP 2.14.2: Port Authority
A wave of community contributions arrives safely in the 2.x line. Important backports from 3.0 improve OpenAPI 3.1 compatibility, MCP spec compliance for output schemas and elicitation, and correct a subtle base_url fallback issue.
🔧
OpenAPI 3.1 support
fixes version detection to properly handle 3.1 specs alongside 3.0.
📋
MCP spec compliance
for root-level
$ref
resolution in output schemas and titled enum elicitation schemas.
Read the release notes
​
FastMCP 2.14.1
Releases
December 15, 2025
FastMCP 2.14.1: 'Tis a Gift to Be Sample
FastMCP 2.14.1 introduces sampling with tools (SEP-1577), enabling servers to pass tools to
ctx.sample()
for agentic workflows where the LLM can automatically execute tool calls in a loop.
🤖
Sampling with tools
lets servers leverage client LLM capabilities for multi-step agentic workflows. The new
ctx.sample_step()
method provides single LLM calls with tool inspection, while
result_type
enables structured outputs via validated Pydantic models.
🔧
AnthropicSamplingHandler
joins the existing OpenAI handler, and both are now promoted from experimental to production-ready status with a unified API.
Read the release notes
​
FastMCP 2.14.0
Releases
December 11, 2025
FastMCP 2.14.0: Task and You Shall Receive
FastMCP 2.14 begins adopting the MCP 2025-11-25 specification, introducing protocol-native background tasks that enable long-running operations to report progress without blocking clients.
⏳
Background Tasks (SEP-1686)
let you add
task=True
to any async tool decorator. Powered by
Docket
for enterprise task scheduling—in-memory backends work out-of-the-box, Redis enables persistence and horizontal scaling.
🔧
OpenAPI Parser Promoted
from experimental to standard with improved performance through single-pass schema processing.
📋
MCP Spec Updates
including SSE polling (SEP-1699), multi-select elicitation (SEP-1330), and tool name validation (SEP-986). Also removes deprecated APIs accumulated across 2.x.
Read the release notes
​
FastMCP 2.13.3
Releases
December 3, 2025
FastMCP 2.13.3: Pin-ish Line
Pins
mcp<1.23
as a precaution due to MCP SDK changes related to the 11/25/25 protocol update that break certain FastMCP patches and workarounds. FastMCP 2.14 introduces proper support for the updated protocol.
Read the release notes
​
FastMCP 2.13.2
Releases
December 1, 2025
FastMCP 2.13.2: Refreshing Changes
Polishes the authentication stack with improvements to token refresh, scope handling, and multi-instance deployments.
🎮
Discord OAuth provider
added as a built-in authentication option.
🔄
Token refresh fixes
for Azure and Google providers, plus OAuth proxy improvements for multi-instance deployments.
🎨
Icon support
added to proxy classes for richer UX.
Read the release notes
​
FastMCP 2.13.1
Releases
November 15, 2025
FastMCP 2.13.1: Heavy Meta
Introduces meta parameter support for
ToolResult
, enabling tools to return supplementary metadata alongside results for patterns like OpenAI’s Apps SDK.
🏷️
Meta parameters
let tools return supplementary metadata alongside results.
🔐
New auth providers
for OCI and Supabase, plus custom token verifiers with DebugTokenVerifier for development.
🔒
Security fixes
for CVE-2025-61920 and safer Cursor deeplink URL validation on Windows.
Read the release notes
​
FastMCP 2.13.0
Releases
October 25, 2025
FastMCP 2.13.0: Cache Me If You Can
FastMCP 2.13 “Cache Me If You Can” represents a fundamental maturation of the framework. After months of community feedback on authentication and state management, this release delivers the infrastructure FastMCP needs to handle production workloads: persistent storage, response caching, and pragmatic OAuth improvements that reflect real-world deployment challenges.
💾
Pluggable storage backends
bring persistent state to FastMCP servers. Built on
py-key-value-aio
, a new library from FastMCP maintainer Bill Easton (
@strawgate
), the storage layer provides encrypted disk storage by default, platform-aware token management, and a simple key-value interface for application state. We’re excited to bring this elegantly designed library into the FastMCP ecosystem - it’s both powerful and remarkably easy to use, including wrappers to add encryption, TTLs, caching, and more to backends ranging from Elasticsearch, Redis, DynamoDB, filesystem, in-memory, and more!
🔐
OAuth maturity
brings months of production learnings into the framework. The new consent screen prevents confused deputy and authorization bypass attacks discovered in earlier versions, while the OAuth proxy now issues its own tokens with automatic key derivation. RFC 7662 token introspection support enables enterprise auth flows, and path prefix mounting enables OAuth-protected servers to integrate into existing web applications. FastMCP now supports out-of-the-box authentication with
WorkOS
and
AuthKit
,
GitHub
,
Google
,
Azure
(Entra ID),
AWS Cognito
,
Auth0
,
Descope
,
Scalekit
,
JWTs
, and
RFC 7662 token introspection
.
⚡
Response Caching Middleware
dramatically improves performance for expensive operations, while
Server lifespans
provide proper initialization and cleanup hooks that run once per server instance instead of per client session.
✨
Developer experience improvements
include Pydantic input validation, icon support, RFC 6570 query parameters for resource templates, improved Context API methods, and async file/directory resources.
Read the release notes
​
FastMCP 2.12.5
Releases
October 17, 2025
FastMCP 2.12.5: Safety Pin
Pins MCP SDK version below 1.17 to ensure the
.well-known
payload appears in the expected location when using FastMCP auth providers with composite applications.
Read the release notes
​
FastMCP 2.12.4
Releases
September 26, 2025
FastMCP 2.12.4: OIDC What You Did There
FastMCP 2.12.4 adds comprehensive OIDC support and expands authentication options with AWS Cognito and Descope providers. The release also includes improvements to logging middleware, URL handling for nested resources, persistent OAuth client registration storage, and various fixes to the experimental OpenAPI parser.
🔐
OIDC Configuration
brings native support for OpenID Connect, enabling seamless integration with enterprise identity providers.
🏢
Enterprise Authentication
expands with AWS Cognito and Descope providers, broadening the authentication ecosystem.
🛠️
Improved Reliability
through enhanced URL handling, persistent OAuth storage, and numerous parser fixes based on community feedback.
Read the release notes
​
FastMCP 2.12.3
Releases
September 17, 2025
FastMCP 2.12.3: Double Time
FastMCP 2.12.3 focuses on performance and developer experience improvements. This release includes optimized auth provider imports that reduce server startup time, enhanced OIDC authentication flows, and automatic inline snapshot creation for testing.
Read the release notes
​
FastMCP 2.12.2
Releases
September 3, 2025
FastMCP 2.12.2: Perchance to Stream
Hotfix for streamable-http transport validation in fastmcp.json configuration files, resolving a parsing error when CLI arguments were merged against the configuration spec.
Read the release notes
​
FastMCP 2.12.1
Releases
September 3, 2025
FastMCP 2.12.1: OAuth to Joy
FastMCP 2.12.1 strengthens OAuth proxy implementation with improved client storage reliability, PKCE forwarding, configurable token endpoint authentication methods, and expanded scope handling based on extensive community testing.
Read the release notes
​
FastMCP 2.12
Releases
August 31, 2025
FastMCP 2.12: Auth to the Races
FastMCP 2.12 represents one of our most significant releases to date. After extensive testing and iteration with the community, we’re shipping major improvements to authentication, configuration, and MCP feature adoption.
🔐
OAuth Proxy
bridges the gap for providers that don’t support Dynamic Client Registration, enabling authentication with GitHub, Google, WorkOS, and Azure through minimal configuration.
📋
Declarative JSON Configuration
introduces
fastmcp.json
as the single source of truth for server settings, making MCP servers as portable and shareable as container images.
🧠
Sampling API Fallback
tackles adoption challenges by letting servers generate completions server-side when clients don’t support the feature, encouraging innovation while maintaining compatibility.
Read the release notes
​
FastMCP 2.11
Releases
August 1, 2025
FastMCP 2.11: Auth to a Good Start
FastMCP 2.11 brings enterprise-ready authentication and dramatic performance improvements.
🔒
Comprehensive OAuth 2.1 Support
with WorkOS AuthKit integration, Dynamic Client Registration, and support for separate resource and authorization servers.
⚡
Experimental OpenAPI Parser
delivers dramatic performance gains through single-pass schema processing and optimized memory usage (enable with environment variable).
💾
Enhanced State Management
provides persistent state across tool calls with a simple dictionary interface, improving context handling and type annotations.
This release emphasizes speed and simplicity while setting the foundation for future enterprise features.
Read the release notes
​
FastMCP 2.10
Releases
July 2, 2025
FastMCP 2.10: Great Spec-tations
FastMCP 2.10 achieves full compliance with the 6/18/2025 MCP specification update, introducing powerful new communication patterns.
💬
Elicitation Support
enables dynamic server-client communication and “human-in-the-loop” workflows, allowing servers to request additional information during execution.
📊
Output Schemas
provide structured outputs for tools, making results more predictable and easier to parse programmatically.
🛠️
Enhanced HTTP Routing
with OpenAPI extensions support and configurable algorithms for more flexible API integration.
This release includes a breaking change to
client.call_tool()
return signatures but significantly expands the interaction capabilities of MCP servers.
Read the release notes
​
FastMCP 2.9
Releases
Blog Posts
June 23, 2025
FastMCP 2.9: MCP-Native Middleware
FastMCP 2.9 is a major release that, among other things, introduces two important features that push beyond the basic MCP protocol.
🤝
MCP Middleware
brings a flexible middleware system for intercepting and controlling server operations - think authentication, logging, rate limiting, and custom business logic without touching core protocol code.
✨
Server-side type conversion
for prompts solves a major developer pain point: while MCP requires string arguments, your functions can now work with native Python types like lists and dictionaries, with automatic conversion handling the complexity.
These features transform FastMCP from a simple protocol implementation into a powerful framework for building sophisticated MCP applications. Combined with the new
File
utility for binary data and improvements to authentication and serialization, this release makes FastMCP significantly more flexible and developer-friendly while maintaining full protocol compliance.
Read more
​
FastMCP 2.8
Releases
Blog Posts
June 11, 2025
FastMCP 2.8: Transform and Roll Out
FastMCP 2.8 is here, and it’s all about taking control of your tools.
This release is packed with new features for curating the perfect LLM experience:
🛠️ Tool Transformation
The headline feature lets you wrap any tool—from your own code, a third-party library, or an OpenAPI spec—to create an enhanced, LLM-friendly version. You can rename arguments, rewrite descriptions, and hide parameters without touching the original code.
This feature was developed in close partnership with Bill Easton. As Bill brilliantly
put it
, “Tool transformation flips Prompt Engineering on its head: stop writing tool-friendly LLM prompts and start providing LLM-friendly tools.”
🏷️ Component Control
Now that you’re transforming tools, you need a way to hide the old ones! In FastMCP 2.8 you can programmatically enable/disable any component, and for everyone who’s been asking what FastMCP’s tags are for—they finally have a purpose! You can now use tags to declaratively filter which components are exposed to your clients.
🚀 Pragmatic by Default
Lastly, to ensure maximum compatibility with the ecosystem, we’ve made the pragmatic decision to default all OpenAPI routes to Tools, making your entire API immediately accessible to any tool-using agent. When the industry catches up and supports resources, we’ll restore the old default — but no reason you should do extra work before OpenAI, Anthropic, or Google!
Read more
​
FastMCP 2.7
Releases
June 6, 2025
FastMCP 2.7: Pare Programming
FastMCP 2.7 has been released!
Most notably, it introduces the highly requested (and Pythonic) “naked” decorator usage:
mcp
=
FastMCP
()
@
mcp
.
tool
def
add
(
a
:
int
,
b
:
int
)
->
int
:
return
a
+
b
In addition, decorators now return the objects they create, instead of the decorated function. This is an important usability enhancement.
The bulk of the update is focused on improving the FastMCP internals, including a few breaking internal changes to private APIs. A number of functions that have clung on since 1.0 are now deprecated.
Read the release notes
​
FastMCP 2.6
Releases
Blog Posts
June 2, 2025
FastMCP 2.6: Blast Auth
FastMCP 2.6 is here!
This release introduces first-class authentication for MCP servers and clients, including pragmatic Bearer token support and seamless OAuth 2.1 integration. This release aligns with how major AI platforms are adopting MCP today, making it easier than ever to securely connect your tools to real-world AI models. Dive into the update and secure your stack with minimal friction.
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Vibe-Testing
Blog Posts
Tutorials
May 21, 2025
Stop Vibe-Testing Your MCP Server
Your tests are bad and you should feel bad.
Stop vibe-testing your MCP server through LLM guesswork. FastMCP 2.0 introduces in-memory testing for fast, deterministic, and fully Pythonic validation of your MCP logic—no network, no subprocesses, no vibes.
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10,000 Stars
Blog Posts
May 8, 2025
Reflecting on FastMCP at 10k stars 🌟
In just six weeks since its relaunch, FastMCP has surpassed 10,000 GitHub stars—becoming the fastest-growing OSS project in our orbit. What started as a personal itch has become the backbone of Python-based MCP servers, powering a rapidly expanding ecosystem. While the protocol itself evolves, FastMCP continues to lead with clarity, developer experience, and opinionated tooling. Here’s to what’s next.
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FastMCP 2.3
Blog Posts
Releases
May 8, 2025
Now Streaming: FastMCP 2.3
FastMCP 2.3 introduces full support for Streamable HTTP, a modern alternative to SSE that simplifies MCP deployments over the web. It’s efficient, reliable, and now the default HTTP transport. Just run your server with transport=“http” and connect clients via a standard URL—FastMCP handles the rest. No special setup required. This release makes deploying MCP servers easier and more portable than ever.
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Proxy Servers
Blog Posts
Tutorials
April 23, 2025
MCP Proxy Servers with FastMCP 2.0
Even AI needs a good travel adapter 🔌
FastMCP now supports proxying arbitrary MCP servers, letting you run a local FastMCP instance that transparently forwards requests to any remote or third-party server—regardless of transport. This enables transport bridging (e.g., stdio ⇄ SSE), simplified client configuration, and powerful gateway patterns. Proxies are fully composable with other FastMCP servers, letting you mount or import them just like local servers. Use
FastMCP.from_client()
to wrap any backend in a clean, Pythonic proxy.
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FastMCP 2.0
Releases
Blog Posts
April 16, 2025
Introducing FastMCP 2.0 🚀
This major release reimagines FastMCP as a full ecosystem platform, with powerful new features for composition, integration, and client interaction. You can now compose local and remote servers, proxy arbitrary MCP servers (with transport translation), and generate MCP servers from OpenAPI or FastAPI apps. A new client infrastructure supports advanced workflows like LLM sampling.
FastMCP 2.0 builds on the success of v1 with a cleaner, more flexible foundation—try it out today!
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Official SDK
Announcements
December 3, 2024
FastMCP is joining the official MCP Python SDK!
FastMCP 1.0 will become part of the official MCP Python SDK!
Read the announcement
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FastMCP 1.0
Releases
Blog Posts
December 1, 2024
Introducing FastMCP 🚀
Because life’s too short for boilerplate.
This is where it all started. FastMCP’s launch post introduced a clean, Pythonic way to build MCP servers without the protocol overhead. Just write functions; FastMCP handles the rest. What began as a weekend project quickly became the foundation of a growing ecosystem.
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