get_alerts
Retrieve weather alerts for any US state using two-letter state codes to monitor hazardous conditions and stay informed about weather warnings.
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:86-132 (registration)Registration of the 'get_alerts' MCP tool, including name, description, input schema, and inline 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:92-131 (handler)The core handler logic for the 'get_alerts' tool: fetches alerts from NWS API using makeNWSRequest, handles errors and empty results, formats alerts with formatAlert, and returns markdown 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:89-91 (schema)Zod input schema for the 'get_alerts' tool, validating the 'state' parameter as a 2-character string.{ state: z.string().length(2).describe("Two-letter state code (e.g. CA, NY)"), },
- src/index.ts:48-58 (helper)Helper function used by 'get_alerts' to format individual alert features into multi-line text strings.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/index.ts:19-35 (helper)Shared helper function for making authenticated fetch requests to the National Weather Service (NWS) API, used by 'get_alerts'.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; } }