get-alerts
Retrieve weather alerts for any US state using its two-letter code to monitor active warnings and advisories.
Instructions
Get weather alerts for a state
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| state | Yes | Two-letter state code (e.g. CA, NY) |
Implementation Reference
- src/index.ts:33-72 (handler)Executes the get-alerts tool: fetches weather alerts from NWS API for a given state code, handles errors and empty results, formats alerts using helper functions, and returns formatted text content.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 formattedAlerts = features.map(formatAlert); const alertsText = `Active alerts for ${stateCode}:\n\n${formattedAlerts.join("\n")}`; return { content: [ { type: "text", text: alertsText, }, ], }; },
- src/index.ts:27-73 (registration)Registers the 'get-alerts' tool with the MCP server, specifying name, description, input schema, and handler function.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 formattedAlerts = features.map(formatAlert); const alertsText = `Active alerts for ${stateCode}:\n\n${formattedAlerts.join("\n")}`; return { content: [ { type: "text", text: alertsText, }, ], }; }, );
- src/index.ts:30-32 (schema)Zod schema for input validation: requires a 2-letter state code.{ state: z.string().length(2).describe("Two-letter state code (e.g. CA, NY)"), },
- src/helper.ts:32-42 (helper)Helper function to format an individual alert feature into a multi-line string summary.export 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"); }
- src/helper.ts:2-19 (helper)Generic helper for making authenticated fetch requests to NWS API endpoints.export async function makeNWSRequest<T>(url: string): Promise<T | null> { const USER_AGENT = "weather-app/1.0"; 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; } }
- src/helper.ts:53-55 (schema)TypeScript interface defining the structure of the NWS alerts API response.export interface AlertsResponse { features: AlertFeature[]; }