@audiolabtools/mcp-server

@audiolabtools/mcp-server

MCP (Model Context Protocol) server that gives any MCP-capable AI (Claude Desktop, Claude Code, Cursor, and others) ten audio-analysis tools, backed by the hosted AudioLab API. It is a thin HTTP client: no local audio engine, no ffmpeg, nothing to compile. It can measure a public URL or a local file on your machine, but the measuring always happens on the hosted API: the file is read here and uploaded there (see Privacy).

Install

Point your MCP client at the package via npx (nothing to install globally):

{
  "mcpServers": {
    "audiolab": {
      "command": "npx",
      "args": ["-y", "@audiolabtools/mcp-server"],
      "env": { "AUDIOLAB_API_KEY": "al_live_yourkey" }
    }
  }
}

Get a key: sign in at https://audiolab.tools/account and generate one (free tier available).

Requirements

• Node ≥ 18: uses the built-in global fetch + AbortSignal.timeout.
• An AUDIOLAB_API_KEY. No ffmpeg, no native dependencies.

Tools

Every tool takes one audio source: a public url or a local path:

• { url: "https://…" }: a public https URL the API fetches server-side.
• { path: "./mix.wav" }: a file on the machine running this server. Files up to 4 MB are sent inline; larger files (up to 150 MB) upload over a signed URL, are analysed, and are swept from storage within the hour. (Local path works only in this stdio server, not the remote /mcp endpoint.)

Tool	Returns
analyze_loudness	Integrated LUFS (EBU R128 / BS.1770-4), true-peak (dBTP), LRA, crest factor, stereo correlation, mono compatibility, tonal balance
check_target	Pass/fail vs a delivery target (spotify / apple-music / youtube / tidal / amazon-music / podcast / ebu-broadcast / atsc-broadcast, or target:"custom" + lufs+tp), with per-metric deltas and an ffmpeg loudnorm fix command
analyze_timeseries	Short-term LUFS over time + downsampled waveform peaks (waveformPoints?)
get_spectrum	FFT magnitude data + 7-band energies
analyze_voice	Voice QA: speech/silence ratio, speaking rate, SNR, noise floor, pause energy, sibilance & clipping risk
get_speech_segments	Voiced regions with start/end + per-segment RMS (auto-trim, chapters)
index_signal	Content-type guess, tags, clipping/silence regions, brightness & dynamics buckets
analyze_profile	One named question, voice, master, provenance, dataset, environment, broadcast or loop, answered with only the lenses it needs. These seven need a paid plan; the free tier gets the basic profile, keyed by stable lens id. Add series:true for the curves, per-block lanes and per-phrase values. Carries a note when the profile’s voice lenses land on non-speech material. Full catalogue: https://audiolab.tools/lenses
compare_loudness	A/B on two sources (urlA/pathA + urlB/pathB), returns both results
analyze_batch	One route over up to 20 sources in a single call (urls and/or paths), per-item ok/data/error. For folder QA, library indexing, or checking a whole release against a target. Each item meters as one call

Example asks to your AI:

• “Analyze the loudness of https://example.com/track.wav” → analyze_loudness with url
• “Is this take usable?” → analyze_profile with profile:"voice"
• “Has this file been re-encoded, and is it all one source?” → analyze_profile with profile:"provenance"
• “Run loudness on ./master.wav” → analyze_loudness with path
• “Does ./mix.mp3 pass Spotify?” → check_target with path + target:"spotify"

Configuration (env)

Var	Default	Purpose
AUDIOLAB_API_KEY	– (required)	Your API key.
AUDIOLAB_API_BASE	https://audiolab.tools/v1	Override the API base (must be https://).
AUDIOLAB_TIMEOUT_MS	330000	Per-request timeout in milliseconds (long files and batches stream server-side and can legitimately take minutes).

Privacy

Analysis happens on the AudioLab API, so the audio does reach audiolab.tools: a url is fetched server-side, and a local path is read here and uploaded to the API (small files in the request body; larger files via a private one-shot signed upload into EU storage). The API returns numbers only and does not keep your audio: a direct request is decoded and discarded inside the request, and a signed upload is swept from storage within the hour (see https://audiolab.tools/privacy). This package has no telemetry and writes nothing to disk. There is no offline mode, and the engine is not published as an installable package. If audio must never leave the machine, don't use a hosted analyser; the in-browser labs on the website measure on-device, but they are for people, not for agents.

Limits

• Local files: up to 150 MB (host bigger ones at a public URL).
• Duration: loudness routes (analyze_loudness, check_target, analyze_timeseries, get_spectrum) handle long files (podcast episodes, full sets, up to ~3 h) via server-side streaming; voice/signal routes are limited to ~7 minutes.
• One file per call (agents loop for many); one-shot (no streaming/realtime).
• Rate and monthly limits are enforced by the API, per key.

Smoke test

node hosted-server.mjs --selftest   # verifies the 10 tools + guards; no network

License

MIT © Nathan Renting