mcp-server-hosting

MCP Server Hosting on AWS

Activate this skill when an MCP server must be reachable by remote agents. For authoring server logic and tool design see mcp-builder; this skill is about where it runs and how it is protected.

When to Use

• Promoting a local stdio MCP server to a remote, multi-tenant service
• Choosing between Lambda, Fargate/ECS, and AgentCore Runtime
• Adding OAuth to an MCP server
• Debugging the 401 / token / retry handshake

Transport

Local, co-located servers use stdio. Remote servers use streamable-HTTP.

from mcp.server.fastmcp import FastMCP

mcp = FastMCP(host="0.0.0.0", stateless_http=True)

@mcp.tool()
def search_docs(query: str, limit: int = 5) -> list[dict]:
    """Search internal documentation. Returns title, url, and snippet per hit.
    Do not use for customer records — see lookup_customer."""
    ...

mcp.run(transport="streamable-http")

Client side:

from mcp.client.streamable_http import streamablehttp_client
from mcp import ClientSession

async with streamablehttp_client(url, headers=auth_headers) as (read, write, _):
    async with ClientSession(read, write) as session:
        await session.initialize()
        result = await session.call_tool("search_docs", {"query": "refund policy"})

stateless_http=True matters on Lambda: with per-request containers there is no reliable place to hold session state between invocations.

Choosing a Host