LiteMCP

LiteMCP class reference: build ASGI-compatible Model Context Protocol servers on FastAPI using decorators for tools, prompts, and resources.

LiteMCP

LiteMCP is an ASGI-compatible Model Context Protocol (MCP) server built on FastAPI. It provides a decorator-based API for registering tools, prompts, and resources.

Class Definition

from agentor.mcp.server import LiteMCP

class LiteMCP(MCPAPIRouter)

Inherits from MCPAPIRouter and adds ASGI compatibility with FastAPI.

Constructor

app = LiteMCP(**kwargs)

**kwargs · dict

Additional arguments passed to MCPAPIRouter. Common options:

• name (str): Server name (default: “agentor-mcp-server”)
• version (str): Server version (default: “0.1.0”)
• instructions (str): Instructions for using the server
• prefix (str): URL prefix for MCP endpoints (default: “/mcp”)
• website_url (str): Server website URL
• icons (List[Icon]): Server icons
• dependencies (List[Callable]): FastAPI dependencies

Methods

serve()

Run the server with uvicorn.

app.serve(
    host="0.0.0.0",
    port=8000,
    enable_cors=True,
    **uvicorn_kwargs
)

host · str · default: "0.0.0.0"

Host to bind the server to

port · int · default: "8000"

Port to bind the server to

enable_cors · bool · default: "true"

Whether to enable CORS middleware with permissive settings

**uvicorn_kwargs · dict

Additional arguments passed to uvicorn.run(), such as:

• reload (bool): Enable auto-reload
• log_level (str): Logging level (“debug”, “info”, “warning”, “error”)
• workers (int): Number of worker processes

run()

Deprecated. Use serve() instead.

app.run(*args, **kwargs)

Decorators

LiteMCP inherits all decorators from MCPAPIRouter:

• @app.tool() - Register a tool
• @app.prompt() - Register a prompt
• @app.resource() - Register a resource
• @app.method() - Register a custom MCP method handler

See MCPAPIRouter for detailed decorator documentation.

ASGI Interface

LiteMCP implements the ASGI interface via __call__, making it compatible with any ASGI server:

async def __call__(scope: dict, receive: Any, send: Any) -> None

This allows you to use LiteMCP with uvicorn CLI:

uvicorn mymodule:app --host 0.0.0.0 --port 8000 --reload

Example Usage

Basic Server

from agentor.mcp.server import LiteMCP

# Create the ASGI app
app = LiteMCP(
    name="my-mcp-server",
    version="1.0.0",
    instructions="A simple MCP server example",
)

# Register a tool
@app.tool(description="Get weather for a location")
def get_weather(location: str) -> str:
    """Get current weather for a location"""
    return f"Weather in {location}: Sunny, 72°F"

# Register a prompt
@app.prompt(description="Generate a greeting")
def greeting(name: str, style: str = "formal") -> str:
    """Generate a personalized greeting"""
    if style == "formal":
        return f"Good day, {name}. How may I assist you today?"
    else:
        return f"Hey {name}! What's up?"

# Register a resource
@app.resource(
    uri="config://settings",
    name="Settings",
    mime_type="application/json"
)
def get_settings(uri: str) -> str:
    """Get application settings"""
    return '{"theme": "dark", "language": "en"}'

if __name__ == "__main__":
    # Run with default settings
    app.serve()

Running with Different Methods

# Method 1: Direct run (simplest)
app.serve()

# Method 2: Run with custom uvicorn settings
app.serve(reload=True, log_level="debug")

# Method 3: Use with uvicorn CLI
# $ uvicorn mymodule:app --host 0.0.0.0 --port 8000 --reload

# Method 4: Programmatic uvicorn
import uvicorn
uvicorn.run(app, host="0.0.0.0", port=8000)

Custom Configuration

from mcp.types import Icon

app = LiteMCP(
    name="weather-mcp-server",
    version="2.0.0",
    instructions="Provides weather information and forecasts",
    prefix="/api/mcp",
    website_url="https://example.com",
    icons=[Icon(url="https://example.com/icon.png", type="image/png")],
)

# Run with CORS disabled and custom port
app.serve(host="127.0.0.1", port=9000, enable_cors=False)

See Also

• MCPAPIRouter - Base router class with decorator API
• CelestoMCPHub - Client for connecting to Celesto AI MCP Hub