coralstack-cmd-ipc-mcp

MCP server adapter that exposes a coralstack-cmd-ipc CommandRegistry as a Model Context Protocol server. Every public command in the registry becomes an MCP tool; tools/list and tools/call are wired through the registry's normal dispatch, so handlers registered by the cmd-ipc #[command] macro or by register_command are callable by any local agent that speaks MCP.

Use case

Built primarily for the Flow runtime, where plugins dynamically register commands via a QuickJS host API and those commands should become available to the user's local agent (Claude Desktop, Cursor, etc.) as MCP tools — without hand-rolling a separate MCP server per plugin.

Usage

use coralstack_cmd_ipc::prelude::*;
use coralstack_cmd_ipc_mcp::McpServerChannel;

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    let registry = CommandRegistry::new(Config::default());

    // Register commands — either a `#[command]`-annotated function /
    // method, or a runtime-built `DynCommand` for dynamic ids. Every
    // public command is reflected as an MCP tool. Private commands
    // (id starts with `_`) are never exposed.
    registry
        .register_command(
            DynCommand::new("plugin.say_hi", |_req: serde_json::Value| async move {
                Ok(serde_json::json!("hi"))
            })
            .description("Greet someone"),
        )
        .await?;

    // Serve over stdio — the transport local agents use when they
    // spawn the server as a child process.
    McpServerChannel::new(registry).serve_stdio().await?;
    Ok(())
}

tools/list reads CommandRegistry::list_commands() at call time, so commands registered after the server starts show up on the next list. tools/call forwards to CommandRegistry::execute_command::<Value, Value>, which routes through the registry's full local/remote/router pipeline.

Feature flags

Defaults enable server and transport-io on rmcp, which is all that's needed for stdio serving. HTTP / WebSocket transports are a follow-up.

Testing

make rs-ready (from the repo root) runs fmt + clippy + the end-to-end smoke tests in tests/server_smoke.rs.