| Component | Type | Name | Description (brief) |
|-----------|------|------|---------------------|
| Tool | tool | search_issues | Search GitHub issues by query |
| Resource | resource | config://settings | Current server configuration |
| Prompt | prompt | summarize_pr | Summarize a pull request for review |

mcp/<name>/
├── server.py          # FastMCP entry point
├── pyproject.toml     # uv project config
├── fastmcp.json       # FastMCP CLI config
└── tests/
    ├── conftest.py    # Client fixture, mock Context
    └── test_server.py # Automated test suite

[tool.pytest.ini_options]
asyncio_mode = "auto"

[dependency-groups]
dev = ["pytest>=8", "pytest-asyncio>=0.25"]

from fastmcp import FastMCP, Context

mcp = FastMCP(
    "server-name",
    instructions="Description of what this server provides and when to use it.",
)

from fastmcp.server.lifespan import lifespan

@lifespan
async def http_lifespan(server):
    import httpx
    async with httpx.AsyncClient() as client:
        yield {"http": client}

mcp = FastMCP("server-name", lifespan=http_lifespan)

Combine lifespans with `|`: `mcp = FastMCP("name", lifespan=db_lifespan | cache_lifespan)`

from typing import Annotated
from pydantic import Field
from fastmcp import Context
from fastmcp.exceptions import ToolError

@mcp.tool(
    annotations={
        "readOnlyHint": True,
        "openWorldHint": True,
    },
)
async def search_items(
    query: Annotated[str, Field(description="Search term to find items.", min_length=1)],
    limit: Annotated[int, Field(description="Max results to return.", ge=1, le=100)] = 10,
    ctx: Context | None = None,
) -> dict:
    """Search for items matching a query.

    Use this tool when you need to find items by keyword. Returns a list of
    matching items with their IDs and titles. Use the limit parameter to
    control result count. Does not search archived items.

    Returns a dictionary with 'items' list and 'total' count.
    """
    if ctx:
        await ctx.info(f"Searching for: {query}")
    try:
        results = await do_search(query, limit)
        return {"items": results, "total": len(results)}
    except ServiceError as e:
        raise ToolError(f"Search failed: {e}")

import json

@mcp.resource("config://settings", mime_type="application/json")
async def get_settings() -> str:
    """Current server configuration."""
    return json.dumps(settings)

@mcp.resource("users://{user_id}/profile")
async def get_user_profile(user_id: str) -> str:
    """User profile by ID."""
    return json.dumps(await fetch_profile(user_id))

from fastmcp.prompts import Message

@mcp.prompt
def summarize_pr(pr_number: int, detail_level: str = "brief") -> list[Message]:
    """Generate a prompt to summarize a pull request."""
    return [Message(
        role="user",
        content=f"Summarize PR #{pr_number} at {detail_level} detail level.",
    )]

from fastmcp import FastMCP
from .issues import issues_server
from .repos import repos_server

mcp = FastMCP("github")
mcp.mount(issues_server, namespace="issues")
mcp.mount(repos_server, namespace="repos")

import pytest
from fastmcp import Client
from server import mcp

@pytest.fixture
async def client():
    async with Client(mcp) as c:
        yield c

async def test_search_items(client):
    result = await client.call_tool("search_items", {"query": "test"})
    assert result.data is not None
    assert not result.is_error

async def test_list_tools(client):
    tools = await client.list_tools()
    names = [t.name for t in tools]
    assert "search_items" in names

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cd mcp/<name> && uv run pytest -v

{
  "mcpServers": {
    "server-name": {
      "command": "uv",
      "args": ["run", "--directory", "/path/to/mcp/<name>", "fastmcp", "run", "server.py"]
    }
  }
}

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