fastmcp-server✓ Pass

SKILL.md Content

---
name: fastmcp-server
description: Complete guide for building MCP servers with FastMCP 3.0 - tools, resources, authentication, providers, middleware, and deployment. Use when creating Python MCP servers or integrating AI models with external tools and data.
version: 1.0.0
author: FastMCP Community
license: MIT
tags: [FastMCP, MCP, Python, AI, Tools, Server, Authentication, Providers]
dependencies: []
---

# FastMCP 3.0 Server Development

Complete reference for building production-ready MCP (Model Context Protocol) servers with FastMCP 3.0 - the fast, Pythonic framework for connecting LLMs to tools and data.

## When to use this skill

**Use FastMCP Server when:**
- Creating a new MCP server in Python
- Adding tools, resources, or prompts to an MCP server
- Implementing authentication (OAuth, OIDC, token verification)
- Setting up middleware for logging, rate limiting, or authorization
- Configuring providers (local, filesystem, skills, custom)
- Building production MCP servers with telemetry and storage
- Upgrading from FastMCP 2.x to 3.0

**Key areas covered:**
- **Tools & Resources** (CORE): Decorators, validation, return types, templates
- **Context & DI** (CORE): MCP context, dependency injection, background tasks
- **Authentication** (SECURITY): OAuth, OIDC, token verification, proxy patterns
- **Authorization** (SECURITY): Scope-based and role-based access control
- **Middleware** (ADVANCED): Request/response pipeline, built-in middleware
- **Providers** (ADVANCED): Local, filesystem, skills, and custom providers
- **Features** (ADVANCED): Pagination, sampling, storage, OpenTelemetry, versioning

## Quick reference

### Core patterns

**Create a server with tools:**
```python
from fastmcp import FastMCP

mcp = FastMCP("MyServer")

@mcp.tool
def add(a: int, b: int) -> int:
    """Add two numbers"""
    return a + b
```

**Create a resource:**
```python
@mcp.resource("data://config")
def get_config() -> dict:
    """Return server configuration"""
    return {"version": "1.0", "debug": False}
```

**Create a resource template:**
```python
@mcp.resource("users://{user_id}/profile")
def get_user_profile(user_id: str) -> dict:
    """Get a user's profile by ID"""
    return fetch_user(user_id)
```

**Create a prompt:**
```python
@mcp.prompt
def review_code(code: str, language: str = "python") -> str:
    """Review code for best practices"""
    return f"Review this {language} code:\n\n{code}"
```

**Run the server:**
```python
if __name__ == "__main__":
    mcp.run()

# Or with transport options:
# mcp.run(transport="sse", host="0.0.0.0", port=8000)
```

### Using context in tools

```python
from fastmcp import FastMCP, Context

mcp = FastMCP("MyServer")

@mcp.tool
def process_data(uri: str, ctx: Context) -> str:
    """Process data with logging and progress"""
    ctx.info(f"Processing {uri}")
    ctx.report_progress(0, 100)
    data = ctx.read_resource(uri)
    ctx.report_progress(100, 100)
    return f"Processed: {data}"
```

### Authentication setup

```python
from fastmcp import FastMCP
from fastmcp.server.auth import BearerAuthProvider

auth = BearerAuthProvider(
    jwks_uri="https://your-provider/.well-known/jwks.json",
    audience="your-api",
    issuer="https://your-provider/"
)

mcp = FastMCP("SecureServer", auth=auth)
```

## Key concepts

### Tools
Functions exposed as executable capabilities for LLMs. Decorated with `@mcp.tool`. Support Pydantic validation, async, custom return types, and annotations (readOnlyHint, destructiveHint).

### Resources & Templates
Static or dynamic data sources identified by URIs. Resources use fixed URIs (`data://config`), templates use parameterized URIs (`users://{id}/profile`). Support MIME types, annotations, and wildcard parameters.

### Context
The `Context` object provides access to MCP features within tools/resources: logging, progress reporting, resource access, LLM sampling, user elicitation, and session state.

### Dependency Injection
Inject values into tool/resource functions using `Depends()`. Supports HTTP requests, access tokens, custom dependencies, and generator-based cleanup patterns.

### Providers
Control where components come from. `LocalProvider` (default, decorator-based), `FileSystemProvider` (load from Python files on disk), `SkillsProvider` (packaged bundles), or custom providers.

### Authentication & Authorization
Multiple auth patterns: token verification (JWT, JWKS), OAuth proxy, OIDC proxy, remote OAuth, and full OAuth server. Authorization via scopes on components and middleware.

### Middleware
Intercept and modify requests/responses. Built-in middleware for rate limiting, error handling, logging, and response size limits. Custom middleware via `@mcp.middleware`.

## Using the references

Detailed documentation is organized in the `references/` folder:

### Getting Started
- **getting-started/installation.md** - Install FastMCP, optional dependencies, verify setup
- **getting-started/upgrade-guide.md** - Migrate from FastMCP 2.x to 3.0
- **getting-started/quickstart.md** - First server, tools, resources, prompts, running

### Server
- **server/server-class.md** - FastMCP server configuration, transport options, tag filtering
- **server/tools.md** - Tool decorator, parameters, validation, return types, annotations
- **server/resources-and-templates.md** - Resources, templates, URIs, wildcards, MIME types

### Context
- **context/mcp-context.md** - Context object, logging, progress, resource access, sampling
- **context/background-tasks.md** - Long-running operations with task support
- **context/dependency-injection.md** - Depends(), custom deps, HTTP request, access tokens
- **context/user-elicitation.md** - Request structured input from users during execution

### Features
- **features/icons.md** - Custom icons for tools, resources, prompts, and servers
- **features/lifespans.md** - Server lifecycle management and startup/shutdown hooks
- **features/client-logging.md** - Send log messages to MCP clients
- **features/middleware.md** - Request/response pipeline, built-in and custom middleware
- **features/pagination.md** - Paginate large component lists
- **features/progress-reporting.md** - Report progress for long-running operations
- **features/sampling.md** - Request LLM completions from the client
- **features/storage-backends.md** - Memory, file, and Redis storage for caching and tokens
- **features/opentelemetry.md** - Distributed tracing and observability
- **features/versioning.md** - Version components and filter by version ranges

### Authentication
- **authentication/token-verification.md** - JWT, JWKS, introspection, static keys, custom
- **authentication/remote-oauth.md** - Delegate auth to upstream OAuth provider
- **authentication/oauth-proxy.md** - Full OAuth proxy with PKCE, client management
- **authentication/oidc-proxy.md** - OpenID Connect proxy with auto-discovery
- **authentication/full-oauth-server.md** - Complete built-in OAuth server

### Authorization
- **authorization.md** - Scope-based access control, middleware authorization, patterns

### Providers
- **providers/local.md** - Default provider, decorator-based component registration
- **providers/filesystem.md** - Load components from Python files on disk
- **providers/skills.md** - Package and distribute component bundles
- **providers/custom.md** - Build custom providers for any component source

## Version history

**v1.0.0** (February 2026)
- Initial release covering FastMCP 3.0 (release candidate)
- 30 reference files across 7 categories
- Complete coverage of tools, resources, context, auth, providers, and features

License

Declared license: MIT

MIT License

Copyright (c) 2026 FastMCP Community

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

View the license in the source repository — the version published there is authoritative.