addLABSCO SUMMARY
The two tools are the least interesting part, deliberately.
Nobody needs a remote server to add two numbers — what people need when writing their first remote MCP server is to know whether the handshake is right, and this repository answers that with a test script that says which step failed. The remote-client notes are the other quiet payoff: the trailing slash, the HTTP flag, the Accept header. Those three details cost most people an evening, and they are written down here.
What it is
A minimal reference implementation of an MCP server with streamable HTTP transport, built with FastMCP against the 2025-06-18 specification. Two arithmetic tools stand in for whatever you will actually build; the value is the surrounding scaffolding — session handling, deployment configs and a test suite that validates the protocol flow end to end.
What you get
- Two tools that exist to prove the wiring works —
addandmultiply, each taking two numbers - The initialization flow handled properly: initialize, the initialized notification, then session-scoped calls
- A test script that walks the whole protocol and reports what passed, so a broken deployment tells you where it broke
- A second test script that runs the same checks against a deployed URL rather than localhost
- Deployment configuration for Railway, Heroku and Render, plus a Dockerfile
- The curl commands for each protocol step, written out, which is the fastest way to understand what a client is actually sending
- A worked remote-client configuration using
mcp-remote, including the details that trip people up — the trailing slash on/mcp/, the HTTP flag and the Accept header for SSE
Requirements
No account and no key. Clone, uv sync, activate the environment and run python main.py; the server comes up at http://localhost:8000/mcp/. HOST defaults to 127.0.0.1 and PORT to 8000 — deployment platforms set them, and FastMCP binds accordingly. The pyproject name is mcp-simple-server (0.1.0). Adding your own tool is a decorated function, and the README shows the pattern.
Setup effort
Build from source — clone the repository, then follow the project's own run instructions
USE CASES
01
Writing your first remote MCP server
Start from a working streamable-HTTP server and replace the two example tools with your own.
02
Checking a deployment actually speaks MCP
Run the deployment test against your hosted URL and see which protocol step fails, instead of guessing from a client error.
03
Understanding what a client sends
Work through the written-out curl sequence — initialize, notify, list tools, call one — to see the protocol on the wire.
04
Connecting a hosted server to a desktop client
Copy the mcp-remote configuration, trailing slash and Accept header included, rather than rediscovering those details.
2 tools
Listed in project docs. Your client may show a different list.
multiplyBEFORE YOU INSTALL
What to know first
Tools you get
2 tools named in the project's documentation.
Requires
- python on PATH
- Python Requires Python >=3.10
INSTALLATION
Connect your client
Server setup
TERMINAL
python main.pyMCP Clients
Claude Desktop — local
CLAUDE DESKTOP — LOCAL · JSON
{
"mcpServers": {
"simple-server": {
"command": "python",
"args": [
"main.py"
],
"cwd": "<YOUR_PATH_TO_MCP_SIMPLE_SERVER>"
}
}
}Claude Desktop — remote
CLAUDE DESKTOP — REMOTE · JSON
{
"mcpServers": {
"simple-server-remote": {
"command": "npx",
"args": [
"-y",
"mcp-remote",
"https://<YOUR_APP>.railway.app/mcp/",
"--allow-http",
"--header",
"Accept: application/json, text/event-stream"
]
}
}
}
