mcp-weather-ts

TypeScript MCP server that exposes US weather from the National Weather Service API to hosts such as Cursor.

The host starts node build/index.js and talks JSON-RPC over stdio. The model never calls NWS itself; it calls this server’s tools (and can read a resource or use a prompt).

How MCP works (tools, resources, prompts, transport): docs/create-mcp.readme.md.

Requirements

• Node.js 22+ (this repo uses ESM and fetch)

• npm

• Network access to https://api.weather.gov (US locations only)

Related MCP server: weather

Setup

npm install
npm run build

tsc writes JavaScript to build/. Cursor must run the built file, not src/index.ts.

Scripts

Mount in Cursor

1. Build (npm run build).

2. Add .cursor/mcp.json in this project:

{
  "mcpServers": {
    "weather": {
      "type": "stdio",
      "command": "node",
      "args": ["${workspaceFolder}/build/index.js"]
    }
  }
}

For all Cursor projects, use %USERPROFILE%\.cursor\mcp.json and a full path to build\index.js instead of ${workspaceFolder}.

3. Open Customize → MCP (or Cursor Settings → MCP) and enable weather.

4. After you change src/, run npm run build again and toggle the server off/on so Cursor restarts the process.

Do not console.log after the server connects: stdout is the MCP wire. Use console.error for logs.

What you can call

Tools

The model (or you, by asking in Agent chat) invokes these with tools/call.

Example chat:

• “Any weather alerts for CA?”

• “Forecast for 39.7456, -97.0892”

Example arguments:

{ "state": "CA" }

{ "latitude": 39.7456, "longitude": -97.0892 }

Resource

Ask the agent to read weather://nws-guide, or use resources/read in a client.

Prompt

In Cursor, pick the Check weather prompt and fill place.

Project layout

src/index.ts              Create McpServer, register, connect stdio
src/tools.ts              get_alerts, get_forecast, test_tool
src/resources.ts          weather://nws-guide
src/prompts.ts            check_weather
src/weather-api-call.ts   NWS fetch + types + alert formatting
src/createTransport.ts    StdioServerTransport + connect
tests/weather-api-call.test.ts
docs/create-mcp.readme.md How to design MCP servers

Startup order in src/index.ts:

1. new McpServer({ name: "weather", version: "1.0.0" })

2. registerWeatherTools / registerWeatherResources / registerWeatherPrompts

3. connectStdioTransport(server)

NWS notes

• Forecasts are not at /points/{lat},{lon}/forecast. Load /points/{lat},{lon} (four decimal places), then follow properties.forecast or properties.forecastHourly.

• NWS requires a User-Agent header (set in weather-api-call.ts).

• Coverage is US (and some territories). Other coordinates often fail.

Troubleshooting

Cursor: Output → MCP Logs.

License

ISC