index.ts•6.49 kB
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { z } from "zod";
import axios from "axios";
const NWS_API_BASE = "https://api.weather.gov";
const USER_AGENT = "weather-app/1.0";
// Create server instance
const server = new McpServer({
name: "weather",
version: "1.0.0",
capabilities: {
resources: {},
tools: {},
},
});
// Create axios instance with default configuration
const api = axios.create({
baseURL: NWS_API_BASE,
headers: {
"User-Agent": USER_AGENT,
"Accept": "application/geo+json",
},
});
// Helper function for making NWS API requests
async function makeNWSRequest<T>(url: string): Promise<T | null> {
try {
const response = await api.get<T>(url);
return response.data;
} catch (error) {
if (axios.isAxiosError(error)) {
console.error("Error making NWS request:", error.message);
if (error.response) {
console.error("Response status:", error.response.status);
console.error("Response data:", error.response.data);
}
} else {
console.error("Unexpected error:", error);
}
return null;
}
}
interface AlertFeature {
properties: {
event?: string;
areaDesc?: string;
severity?: string;
status?: string;
headline?: string;
};
}
// Format alert data
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: ${props.headline || "No headline"}`,
"---",
].join("\n");
}
interface ForecastPeriod {
name?: string;
temperature?: number;
temperatureUnit?: string;
windSpeed?: string;
windDirection?: string;
shortForecast?: string;
}
interface AlertsResponse {
features: AlertFeature[];
}
interface PointsResponse {
properties: {
forecast?: string;
};
}
interface ForecastResponse {
properties: {
periods: ForecastPeriod[];
};
}
// Register weather tools
server.tool(
"get-alerts",
"Get weather alerts for a state",
{
state: z.string().length(2).describe("Two-letter state code (e.g. CA, NY)"),
},
async ({ state }) => {
const stateCode = state.toUpperCase();
const alertsData = await makeNWSRequest<AlertsResponse>(`/alerts?area=${stateCode}`);
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 formattedAlerts = features.map(formatAlert);
const alertsText = `Active alerts for ${stateCode}:\n\n${formattedAlerts.join("\n")}`;
return {
content: [
{
type: "text",
text: alertsText,
},
],
};
},
);
server.tool(
"get-forecast",
"Get weather forecast for a location",
{
latitude: z.number().min(-90).max(90).describe("Latitude of the location"),
longitude: z.number().min(-180).max(180).describe("Longitude of the location"),
},
async ({ latitude, longitude }) => {
// Get grid point data
const pointsData = await makeNWSRequest<PointsResponse>(
`/points/${latitude.toFixed(4)},${longitude.toFixed(4)}`
);
if (!pointsData) {
return {
content: [
{
type: "text",
text: `Failed to retrieve grid point data for coordinates: ${latitude}, ${longitude}. This location may not be supported by the NWS API (only US locations are supported).`,
},
],
};
}
const forecastUrl = pointsData.properties?.forecast;
if (!forecastUrl) {
return {
content: [
{
type: "text",
text: "Failed to get forecast URL from grid point data",
},
],
};
}
// Get forecast data - using full URL since the forecast URL is absolute
const forecastData = await makeNWSRequest<ForecastResponse>(forecastUrl);
if (!forecastData) {
return {
content: [
{
type: "text",
text: "Failed to retrieve forecast data",
},
],
};
}
const periods = forecastData.properties?.periods || [];
if (periods.length === 0) {
return {
content: [
{
type: "text",
text: "No forecast periods available",
},
],
};
}
// Format forecast periods
const formattedForecast = periods.map((period: ForecastPeriod) =>
[
`${period.name || "Unknown"}:`,
`Temperature: ${period.temperature || "Unknown"}°${period.temperatureUnit || "F"}`,
`Wind: ${period.windSpeed || "Unknown"} ${period.windDirection || ""}`,
`${period.shortForecast || "No forecast available"}`,
"---",
].join("\n"),
);
return {
content: [
{
type: "text",
text: formattedForecast.join("\n"),
},
],
};
},
);
// Start the server
async function main() {
try {
const transport = new StdioServerTransport();
// Set up error handlers before connecting
process.on('uncaughtException', (error) => {
console.error('Uncaught exception:', error);
});
process.on('unhandledRejection', (reason, promise) => {
console.error('Unhandled rejection at:', promise, 'reason:', reason);
});
// Connect to the transport
await server.connect(transport);
console.error('Weather MCP Server running on stdio');
// Handle graceful shutdown
process.on('SIGINT', () => {
console.error('Received SIGINT signal');
process.exit(0);
});
process.on('SIGTERM', () => {
console.error('Received SIGTERM signal');
process.exit(0);
});
// Keep the process alive
await new Promise(() => {});
} catch (error) {
console.error('Fatal error in main():', error);
process.exit(1);
}
}
// Start the server and handle any errors
main().catch((error) => {
console.error('Error starting server:', error);
process.exit(1);
});