mcp -java-sse-http-demo

This MCP server implements a Weather service using the Java SSE HTTP transport. It demonstrates end-to-end model context usage where a local weather MCP tool can be invoked via a remote SSE transport, enabling the MCP client to query weather data for multiple cities and return a summarized forecast. The server is designed to work with the MCP ecosystem, including a lightweight agent that can discover and call tools such as a geolocation fetch service and the weather service itself, all through the SSE stream. You can connect to the SSE endpoint, observe tool invocations, and see the agent aggregate forecasts (e.g., which city will be warmest tomorrow).

Prerequisites:

• Java JDK 8+ and Maven
• Optional: Git if cloning from a repo

1. Build the MCP server

mvn clean package

2. Run the MCP server (SSE HTTP transport)

java -jar mcp-server/target/mcp-server-1.0-SNAPSHOT.jar

3. (Optional) Configure a client to connect via SSE

• Ensure the server is reachable at http://localhost:8080/sse
• Example client config (MCP client) can reference the SSE transport endpoint

Notes:

• The server demonstrates how to expose weather-related tools over an SSE transport and how an agent can orchestrate calls to a fetch service and the weather service.
• If you modify the server, rebuild with Maven to apply changes.

Tips and caveats:

• The README demonstrates an SSE endpoint at /sse and a message endpoint at /mcp/message. Ensure those routes are accessible in your environment.
• When testing locally, you may need to start additional services such as the fetch websearch MCP server that Weather relies on for city lat/long lookups.
• If you encounter connection or timeout issues, adjust the read_timeout_seconds in your MCP server configuration to match network latency.
• You can modify environment variables such as MCP_LOG_LEVEL to get more verbose logs during debugging.