Sheet Music OMR

sheet-music-mcp

Six MCP servers that let an AI assistant work with sheet music: read a photo of a score, render it, play single voice parts, edit it as text, compare editions and follow a singer in real time. Built for choir rehearsal.

"Here is a photo of page 1. Convert it to MusicXML and play me the alto part at 80% tempo."

The assistant calls omr-mcp to recognise the page, then synth-mcp to render the alto line to a WAV file.

Servers

Each server is a separate PyPI package, listed in the MCP Registry as io.github.raulkivi/<server>.

All servers use stdio and need Python 3.11+ (3.12+ for pitch-mcp) and uv.

Quick start

Add the servers you need to your MCP client configuration (claude_desktop_config.json, Cursor's mcp.json and similar):

{
  "mcpServers": {
    "omr": { "command": "uvx", "args": ["omr-mcp"] },
    "render": { "command": "uvx", "args": ["render-mcp"] },
    "synth": {
      "command": "uvx",
      "args": ["synth-mcp"],
      "env": { "SYNTH_SOUNDFONT_PATH": "/path/to/soundfont.sf2" }
    }
  }
}

Claude Code:

claude mcp add omr -- uvx omr-mcp

Each server's SETUP.md walks through installation for non-developers, and examples/ has ready-made configs for Claude Desktop, Cursor, Windsurf, Continue and Zed. Every server has a health_check tool that reports missing system libraries or files.

Security

• PyPI releases use Trusted Publishing from GitHub Actions and carry PEP 740 attestations; no API tokens are stored.
• Workflow actions are pinned to commit SHAs; Dependabot keeps them and the Python dependencies current.
• Pull requests run a Claude security review and unicode-smuggling-guard, which blocks hidden Unicode in code, docs and agent files.
• Tools that write files (output_path) accept only paths inside SHEET_MUSIC_OUTPUT_ROOT (default: the server working directory), with the expected file extension, and never overwrite an existing file. The omr-mcp Audiveris download is verified against a pinned SHA-256.
• Secret scanning and push protection are on.
• Report vulnerabilities privately: see SECURITY.md.

Background

The project started as a choir assistant: help singers digitize, practice with, and navigate sheet music on their phones.

Goals

1. Digitize paper sheet music (photograph → digital score)
2. Export sheet music as a PDF
3. Play sheet music in individual voices (Soprano, Alto, Tenor, Bass) or combined
4. Show the current position in the score while singing (tempo tracking)
5. Show pitch accuracy in real time (too high / too low / on pitch)
6. Identify where in a score a singer currently is based on a hummed or sung melody
7. Compare two scores (editions, arrangements, OMR output vs. reference) and report structured diffs

Delivery phases

Known limitation: omr-mcp's default engine (oemer) flattens multi-staff SATB scores into one part. Pass engine="audiveris" for choir scores; it needs 300+ DPI images.

Data flow

Paper score
    │  (photo)
    ▼
[omr-mcp]
    │  MusicXML
    ├──────────────────────────► [render-mcp] ──► PDF / PNG         (goal 2)
    │
    ├──────────────────────────► [synth-mcp]                        (goal 3)
    │                                │  voice selection + tempo
    │                                ▼
    │                            Audio file
    │
    ├──────────────────────────► [musicxml-abc-mcp]
    │                                │  ABC text
    │                                ▼
    │                            Claude (reads / edits)
    │                                │  ABC text (edited)
    │                                ▼
    │                            [musicxml-abc-mcp]
    │                                │  MusicXML (AI-edited)
    │                                ▼
    │                            (back into pipeline)
    │
    ├──────────────────────────► [pitch-mcp]
    │                                │  loads reference score
    │                                ▲  microphone audio stream
    │                                │
    │                            score position + pitch accuracy    (goals 4, 5, 6)
    │
    └──────────────────────────► [comparer-mcp]  (also compares against any MusicXML)
                                     │  reference score
                                     ▲  second MusicXML (edition / arrangement / OMR output)
                                     │
                                 structured diff                    (goal 7)

Why ABC notation?

ABC is a compact, text-based music notation format that LLMs can read and edit directly (unlike the verbose XML of MusicXML). The musicxml-abc-mcp server enables AI-assisted score editing: MusicXML → ABC → Claude edits → ABC → MusicXML.

Technology stack

Development

Each server has its own virtual environment managed by uv. Never share venvs between servers, and use uv sync / uv add rather than pip install.

cd synth-mcp
uv sync --extra dev
uv run pytest -m "not integration"   # what CI runs, on Python 3.12 and 3.13
uv run pytest -m integration         # needs the real OMR/audio backends

System libraries for local development:

Free SF2 soundfonts are listed in synth-mcp/README.md.

Releases: bump the version in pyproject.toml, __init__.py, uv.lock and server.json, then push a <server>/vX.Y.Z tag. publish.yml publishes to PyPI and the MCP Registry.

Documentation

• docs/conventions.md — coding and structural conventions shared across all servers
• docs/sources.md — references and sources
• docs/SETUP_UX_PLAN.md — end-user packaging plan (PyPI, installers, setup docs)
• Each server has its own docs/ folder with PLAN.md, HANDOVER.md, requirements.md, and architecture.md

License

MIT