// Copyright (c) 2026 Adin Kwok <adin@adin.dev>
import { z } from "zod";
import type { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import type { AbletonOSC } from "../osc-client.js";
export function registerTransportTools(server: McpServer, osc: AbletonOSC) {
server.tool("transport_play", "Start Ableton Live playback", {}, async () => {
osc.send("/live/song/start_playing");
return { content: [{ type: "text", text: "Playback started." }] };
});
server.tool("transport_stop", "Stop Ableton Live playback", {}, async () => {
osc.send("/live/song/stop_playing");
return { content: [{ type: "text", text: "Playback stopped." }] };
});
server.tool("transport_continue", "Resume playback from current position", {}, async () => {
osc.send("/live/song/continue_playing");
return { content: [{ type: "text", text: "Playback resumed." }] };
});
server.tool(
"get_tempo",
"Get the current song tempo in BPM",
{},
async () => {
const [bpm] = await osc.query("/live/song/get/tempo");
return { content: [{ type: "text", text: `Current tempo: ${bpm} BPM` }] };
},
);
server.tool(
"set_tempo",
"Set the song tempo in BPM",
{ bpm: z.number().min(20).max(999).describe("Tempo in BPM") },
async ({ bpm }) => {
osc.send("/live/song/set/tempo", bpm);
return { content: [{ type: "text", text: `Tempo set to ${bpm} BPM.` }] };
},
);
server.tool(
"set_time_signature",
"Set the song time signature",
{
numerator: z.number().int().min(1).max(99).describe("Beats per bar"),
denominator: z.number().int().min(1).max(16).describe("Beat value (e.g. 4 = quarter note)"),
},
async ({ numerator, denominator }) => {
osc.send("/live/song/set/signature_numerator", numerator);
osc.send("/live/song/set/signature_denominator", denominator);
return { content: [{ type: "text", text: `Time signature set to ${numerator}/${denominator}.` }] };
},
);
server.tool(
"toggle_metronome",
"Turn the metronome on or off",
{ enabled: z.boolean().describe("true = on, false = off") },
async ({ enabled }) => {
osc.send("/live/song/set/metronome", enabled ? 1 : 0);
return { content: [{ type: "text", text: `Metronome ${enabled ? "on" : "off"}.` }] };
},
);
server.tool(
"set_song_position",
"Jump to a position in the song (in beats)",
{ beats: z.number().min(0).describe("Position in beats") },
async ({ beats }) => {
osc.send("/live/song/set/current_song_time", beats);
return { content: [{ type: "text", text: `Song position set to beat ${beats}.` }] };
},
);
server.tool("undo", "Undo the last action in Ableton", {}, async () => {
osc.send("/live/song/undo");
return { content: [{ type: "text", text: "Undo performed." }] };
});
server.tool("redo", "Redo the last undone action in Ableton", {}, async () => {
osc.send("/live/song/redo");
return { content: [{ type: "text", text: "Redo performed." }] };
});
}
