npm init -y --> creates package json npm install @modelcontextprotocol/sdk zod@3 -- install mcp sdk and zod for data validation mkdir src --> makes src folder touch src/index.ts --> makes index.ts file
****replace package.json content bby this --> this will create module format and add scriot for build { "name": "mcpserver", "version": "1.0.0", "description": "", "type": "module", "main": "index.js", "bin": { "weather": "./build/index.js" }, "scripts": { "test": "echo "Error: no test specified" && exit 1", "build": "tsc && chmod 755 build/index.js" }, "files": [ "build" ], "keywords": [], "author": "", "license": "ISC", "dependencies": { "@modelcontextprotocol/sdk": "^1.22.0", "install": "^0.13.0", "pm": "^2.2.6", "zod": "^3.25.76" } }
****Create a tsconfig.json in the root of your project:
{
"compilerOptions": {
"target": "ES2022",
"module": "Node16",
"moduleResolution": "Node16",
"outDir": "./build",
"rootDir": "./src",
"strict": true,
"esModuleInterop": true,
"skipLibCheck": true,
"forceConsistentCasingInFileNames": true
},
"include": ["src/**/*"],
"exclude": ["node_modules"]
}
then add thuis code in index.ts
// Import MCP server framework
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
// zod for input validation
import { z } from "zod";
// Base URL for the US National Weather Service API
const NWS_API_BASE = "https://api.weather.gov";
// Custom User-Agent required by NWS API
const USER_AGENT = "weather-app/1.0";
// Create an MCP server instance with basic metadata (NEW API – no capabilities)
const server = new McpServer({
name: "weather",
version: "1.0.0",
});
// ---------------------------------------------
// Helper: General fetch wrapper for NWS API
// ---------------------------------------------
async function makeNWSRequest<T>(url: string): Promise<T | null> {
const headers = {
"User-Agent": USER_AGENT,
Accept: "application/geo+json",
};
try {
const response = await fetch(url, { headers });
if (!response.ok) {
throw new Error(`HTTP error! status: ${response.status}`);
}
return (await response.json()) as T;
} catch (error) {
console.error("Error making NWS request:", error);
return null;
}
}
// ---------------------------------------------
// Types for API responses
// ---------------------------------------------
interface AlertFeature {
properties: {
event?: string;
areaDesc?: string;
severity?: string;
status?: string;
headline?: string;
};
}
interface ForecastPeriod {
name?: string;
temperature?: number;
temperatureUnit?: string;
windSpeed?: string;
windDirection?: string;
shortForecast?: string;
}
interface AlertsResponse {
features: AlertFeature[];
}
interface PointsResponse {
properties: {
forecast?: string;
};
}
interface ForecastResponse {
properties: {
periods: ForecastPeriod[];
};
}
// ---------------------------------------------
// Helper: Format alert into readable text
// ---------------------------------------------
function formatAlert(feature: AlertFeature): string {
const props = feature.properties;
return [
`Event: ${props.event || "Unknown"}`,
`Area: ${props.areaDesc || "Unknown"}`,
`Severity: ${props.severity || "Unknown"}`,
`Status: ${props.status || "Unknown"}`,
`Headline: ${props.headline || "No headline"}`,
"---",
].join("\n");
}
// ---------------------------------------------
// TOOL #1 — GET WEATHER ALERTS FOR A STATE
// ---------------------------------------------
server.tool(
"get_alerts",
"Get weather alerts for a state",
{
state: z.string().length(2).describe("Two-letter state code (e.g. CA, NY)"),
},
async ({ state }) => {
const stateCode = state.toUpperCase();
const alertsUrl = `${NWS_API_BASE}/alerts?area=${stateCode}`;
const alertsData = await makeNWSRequest<AlertsResponse>(alertsUrl);
if (!alertsData) {
return {
content: [{ type: "text", text: "Failed to retrieve alerts data" }],
};
}
const features = alertsData.features || [];
if (features.length === 0) {
return {
content: [{ type: "text", text: `No active alerts for ${stateCode}` }],
};
}
const text = `Active alerts for ${stateCode}:\n\n${features
.map(formatAlert)
.join("\n")}`;
return { content: [{ type: "text", text }] };
}
);
// ---------------------------------------------
// TOOL #2 — GET WEATHER FORECAST FOR COORDINATES
// ---------------------------------------------
server.tool(
"get_forecast",
"Get weather forecast for a location",
{
latitude: z.number().min(-90).max(90).describe("Latitude"),
longitude: z.number().min(-180).max(180).describe("Longitude"),
},
async ({ latitude, longitude }) => {
const pointsUrl = `${NWS_API_BASE}/points/${latitude.toFixed(
4
)},${longitude.toFixed(4)}`;
const pointsData = await makeNWSRequest<PointsResponse>(pointsUrl);
if (!pointsData) {
return {
content: [
{
type: "text",
text: `Failed to retrieve grid point data for ${latitude}, ${longitude}. Only US locations are supported.`,
},
],
};
}
const forecastUrl = pointsData.properties?.forecast;
if (!forecastUrl) {
return {
content: [{ type: "text", text: "No forecast URL found for location" }],
};
}
const forecastData = await makeNWSRequest<ForecastResponse>(forecastUrl);
if (!forecastData) {
return { content: [{ type: "text", text: "Failed to retrieve forecast" }] };
}
const periods = forecastData.properties?.periods || [];
if (periods.length === 0) {
return { content: [{ type: "text", text: "No forecast periods available" }] };
}
const text = `Forecast for ${latitude}, ${longitude}:\n\n${periods
.map((p) =>
[
`${p.name}:`,
`Temperature: ${p.temperature}°${p.temperatureUnit}`,
`Wind: ${p.windSpeed} ${p.windDirection}`,
`${p.shortForecast}`,
"---",
].join("\n")
)
.join("\n")}`;
return { content: [{ type: "text", text }] };
}
);
// ---------------------------------------------
// MAIN ENTRYPOINT — Start MCP Server
// ---------------------------------------------
async function main() {
const transport = new StdioServerTransport();
await server.connect(transport);
console.error("Weather MCP Server running on stdio");
}
// Start and handle fatal errors
main().catch((error) => {
console.error("Fatal error in main():", error);
process.exit(1);
});
then npm install --save-dev @types/node npm install -g typescript npm run build node build/index.js
then to connect to claude desktop go to terminal and paste this open ~/Library/Application\ Support/Claude/claude_desktop_config.json then you will see your config json, but go to thid folder and paste { "mcpServers": { "weather-server": { "command": "node", "args": ["/Users--> path to your index.js file and close it with /"] } } } save it now you can restart claude desktop and can see your mcp server then chat on claude desktop and ask it to fetch weather data by city name or by latitude and longitude
after getting the gitrepo: git clone (thisrepourl) npm install npm run build node build/index.js