mcp

A hand-rolled MCP (Model Context Protocol) server plus two client demos that talk to it over Streamable HTTP, protocol version 2026-07-28:

• mcp-server/ — the server. Java 17, Gradle. See mcp-server/README.md for the full design and options.
• mcp-client/ — a Java 17 client (McpClient + a Demo runner).
• mcp-client-kt/ — the same client ported to Kotlin 1.5 (McpClient + a Demo runner). Targets Java 11 bytecode since Kotlin 1.5 predates JVM 17 target support; uses its own Gradle 7.6.4 wrapper for compatibility with the 1.5.x Kotlin Gradle plugin.

Each module is a standalone Gradle project (its own gradlew) — there is no root build.

Running the demo

1. Start the server

cd mcp-server
./gradlew run

This starts the server on http://127.0.0.1:3000/mcp against the mcp-server checkout itself as the sandboxed workspace root. Leave it running in this terminal; use --args="--root /path/to/workspace" to point it at a different directory, or see mcp-server/README.md for every flag.

2a. Run the Java client demo

In a second terminal:

cd mcp-client
./gradlew run

To point at a different server: ./gradlew run --args="--url http://127.0.0.1:3000/mcp".

2b. Run the Kotlin client demo

In a second terminal:

cd mcp-client-kt
./gradlew run

Same --args="--url ..." override as the Java client.

Both demos drive every feature kind once — discovery, tools, resources, resource templates, prompts, and completion — plus a sandbox-escape refusal and an unknown-method error, printing each JSON-RPC result and the _meta/resultType envelope that comes back with it.

3. Stop the server

Ctrl-C in the server's terminal, or from another shell: lsof -ti :3000 | xargs kill.