Click on "Install Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@MCP Weather Servercheck for any active weather alerts in California"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
MCP WEATHER SERVER WRITTEN IN TYPESCRIPT
Protocol Map
This weather MCP server implements the Model Context Protocol (MCP) to provide weather data through a standardized interface. Below is the complete protocol mapping showing how the server communicates with MCP clients.
Server Information
Name:
weatherVersion:
1.0.0Transport: STDIO (Standard Input/Output)
Protocol: Model Context Protocol
Capabilities
{
"capabilities": {
"tools": {
"listChanged": true
}
}
}Tools
The server exposes two tools for weather data retrieval:
1. get_alerts
Retrieves active weather alerts for a US state.
Input Schema:
{
"type": "object",
"properties": {
"state": {
"type": "string",
"description": "Two-letter US state code (e.g. CA, NY)",
"minLength": 2,
"maxLength": 2
}
},
"required": ["state"]
}Example Request:
{
"method": "tools/call",
"params": {
"name": "get_alerts",
"arguments": {
"state": "CA"
}
}
}Example Response:
{
"content": [
{
"type": "text",
"text": "Event: Heat Advisory\nArea: Los Angeles County\nSeverity: Moderate\nDescription: Dangerously hot conditions...\nInstructions: Drink plenty of fluids..."
}
]
}Error Response:
{
"content": [
{
"type": "text",
"text": "Unable to fetch alerts or no alerts found."
}
]
}2. get_forecast
Retrieves weather forecast for a specific location using latitude and longitude coordinates.
Input Schema:
{
"type": "object",
"properties": {
"latitude": {
"type": "number",
"description": "Latitude of the location",
"minimum": -90,
"maximum": 90
},
"longitude": {
"type": "number",
"description": "Longitude of the location",
"minimum": -180,
"maximum": 180
}
},
"required": ["latitude", "longitude"]
}Example Request:
{
"method": "tools/call",
"params": {
"name": "get_forecast",
"arguments": {
"latitude": 38.5816,
"longitude": -121.4944
}
}
}Example Response:
{
"content": [
{
"type": "text",
"text": "Tonight:\nTemperature: 65°F\nWind: 5 mph SW\nForecast: Partly cloudy with a slight chance of showers.\n---\nTomorrow:\nTemperature: 78°F\nWind: 10 mph W\nForecast: Sunny skies throughout the day."
}
]
}Error Responses:
{
"content": [
{
"type": "text",
"text": "Failed to retrieve grid point data for coordinates: 38.5816, -121.4944. This location may not be supported by the NWS API (only US locations are supported)."
}
]
}Communication Flow
sequenceDiagram
participant Client as MCP Client (Claude)
participant Server as Weather Server
participant NWS as National Weather Service API
Client->>Server: Initialize Connection (STDIO)
Server->>Client: Server Info + Capabilities
Client->>Server: List Tools
Server->>Client: [get_alerts, get_forecast]
Client->>Server: Call Tool: get_forecast(lat, lon)
Server->>NWS: GET /points/{lat},{lon}
NWS->>Server: Grid Point Data
Server->>NWS: GET {forecast_url}
NWS->>Server: Forecast Data
Server->>Client: Formatted Forecast Text
Client->>Server: Call Tool: get_alerts(state)
Server->>NWS: GET /alerts/active/area/{state}
NWS->>Server: Active Alerts
Server->>Client: Formatted Alerts TextProtocol Messages
Initialization
Client → Server:
{
"jsonrpc": "2.0",
"id": 1,
"method": "initialize",
"params": {
"protocolVersion": "2024-11-05",
"capabilities": {},
"clientInfo": {
"name": "Claude Desktop",
"version": "1.0.0"
}
}
}Server → Client:
{
"jsonrpc": "2.0",
"id": 1,
"result": {
"protocolVersion": "2024-11-05",
"capabilities": {
"tools": {
"listChanged": true
}
},
"serverInfo": {
"name": "weather",
"version": "1.0.0"
}
}
}Tool Discovery
Client → Server:
{
"jsonrpc": "2.0",
"id": 2,
"method": "tools/list"
}Server → Client:
{
"jsonrpc": "2.0",
"id": 2,
"result": {
"tools": [
{
"name": "get_alerts",
"description": "Get weather alerts for a US state.",
"inputSchema": {
"type": "object",
"properties": {
"state": {
"type": "string",
"description": "Two-letter US state code (e.g. CA, NY)"
}
},
"required": ["state"]
}
},
{
"name": "get_forecast",
"description": "Get weather forecast for a location.",
"inputSchema": {
"type": "object",
"properties": {
"latitude": {
"type": "number",
"description": "Latitude of the location"
},
"longitude": {
"type": "number",
"description": "Longitude of the location"
}
},
"required": ["latitude", "longitude"]
}
}
]
}
}External API Integration
National Weather Service API
The server integrates with the following NWS API endpoints:
Endpoint | Purpose | Rate Limit |
| Retrieve active alerts for a state | User-Agent required |
| Get grid point metadata | User-Agent required |
| Retrieve detailed forecast | User-Agent required |
Required Headers:
User-Agent: weather-app/1.0
Accept: application/geo+jsonError Handling
The server implements graceful error handling for:
Invalid coordinates: Returns error message for non-US locations
Network failures: Returns "Unable to fetch..." messages
Missing data: Returns "No active alerts" or similar user-friendly messages
API errors: Catches and handles HTTP errors from NWS API
Transport Layer
Type: STDIO (Standard Input/Output)
Encoding: UTF-8
Message Format: JSON-RPC 2.0
Framing: Newline-delimited JSON
Security Considerations
Input Validation: All parameters are validated against schema
Rate Limiting: Respects NWS API rate limits
Error Sanitization: External API errors are sanitized before returning to client
No Authentication: Server uses public NWS API (no credentials required)
Logging
STDIO Servers: All logs written to
stderr(neverstdout)Log Location: Configured in MCP client (e.g.,
~/Library/Logs/Claude/mcp-server-weather.log)Log Level: Errors and warnings only (to avoid STDIO corruption)