forscore-mcp

Clean up the metadata in a forScore sheet-music library in bulk: titles, composers, catalogue references (Op., BWV, K., …), keys, genres, tags, ratings and more. It works through an AI assistant (an MCP server and a Claude Code plugin; Claude and other LLMs) or from the command line.

Not affiliated with or endorsed by forScore LLC. forScore is a trademark of forScore LLC. The tool reads forScore's internal library database, which is not a public API, and writes changes through forScore's own Metadata CSV import, as forScore's support recommends. Data is still injected into forScore as-is, and the tool cannot guarantee that it works correctly or preserves existing data. Always check forScore's import preview before tapping Save.

Features

• Read:
  • every score and bookmark with its metadata (filtered and paged for large libraries)
  • every composer, genre, tag, label and library in use
  • setlists
• Bulk-edit titles, composers, references, keys, genres, tags, labels, rating, difficulty and duration, for scores and bookmarks.
• Rename or merge a composer, genre or tag everywhere it is used.
• Audit for likely duplicates, identical PDFs, file names that differ from titles, and composer sort names worth checking.
• Check sync: compare the library with what synced devices receive.
• Conventions guide for AI assistants, so their edits stay consistent: full composer names, Op. 69 No. 2 references, genre as style period. See conventions.md.

How it works

1. Read: the tool opens forScore's library database on the Mac read-only and checks its layout every time. It refuses to work with anything it does not recognise.
2. Propose: the assistant (or you) writes a changeset, a small JSON description of the changes. It is previewed as a per-score diff, and nothing is written yet.
3. Import: the changeset becomes a CSV in forScore's own Metadata format, and the tool hands it to forScore. In forScore, open Backups › Metadata (CSV) › Import, tap the file, check forScore's preview and tap Save. forScore applies it and syncs it to your other devices.
4. Verify or undo: the tool checks field by field that the import applied. Any import can be reverted with a second, generated CSV.

forScore can stay open throughout.

Requirements

• A Mac with forScore. The library database only exists on the Mac; iPad-only setups are not supported.
• uv (brew install uv).
• Full Disk Access for the app that runs the tool (Terminal, Claude, Cursor, …), because forScore's data sits in a protected app container: System Settings › Privacy & Security › Full Disk Access.

Install

Claude Code (plugin: MCP server + skill)

/plugin install forscore --marketplace Soham-Chatt/forscore-mcp

Or from a shell: claude plugin install forscore --marketplace Soham-Chatt/forscore-mcp. On older Claude Code versions, run /plugin marketplace add Soham-Chatt/forscore-mcp and then /plugin install forscore@forscore-mcp.

Update with claude plugin update forscore@forscore-mcp, or turn on auto-update under Marketplaces in /plugin. The plugin needs Claude Code, or Claude Desktop through the MCP configuration below. claude.ai on the web and Cowork cannot reach a Mac's local library.

Other MCP clients (Claude Desktop, Cursor, VS Code, Codex, Gemini CLI, …)

Add the server to the client's MCP configuration. For Claude Desktop that is ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "forscore": {
      "command": "uvx",
      "args": ["forscore-mcp"]
    }
  }
}

It is also listed in the official MCP registry as io.github.Soham-Chatt/forscore-mcp. Agents without MCP support can use the CLI with --json; see AGENTS.md.

Command line

uv tool install forscore-mcp
forscore-mcp doctor

doctor checks library access, sync state and the write mode, and explains how to fix any problem it finds.

Usage

Ask the assistant things like "Clean up the composers in my forScore library" or "Fill in the opus numbers for my Chopin scores". It follows the bundled conventions guide unless told otherwise, and proposes a table of changes. Once you approve them, it previews them and creates the import for forScore.

Command line:

forscore-mcp list chopin                  # search scores and bookmarks
forscore-mcp list --missing composers     # filters: --composer --genre --tag --library --kind
forscore-mcp show "Kinderszenen > Träumerei"   # one score or bookmark
forscore-mcp values composers             # values in use, with counts and sort names
forscore-mcp setlists                     # setlists and their items
forscore-mcp audit                        # likely duplicates, file names, sort names
forscore-mcp preview changes.json         # dry run of a changeset
forscore-mcp apply changes.json --yes     # create the import CSV and hand it to forScore
forscore-mcp verify <import id>           # after Save in forScore: did everything apply?
forscore-mcp undo <import id> --yes       # a CSV that restores the previous values
forscore-mcp sync-check                   # do synced devices get the same metadata?
forscore-mcp key "E♭ major"               # key name ↔ forScore's internal code

Add --json to any command for machine-readable output.

Changesets

See examples/changeset.example.json:

{
  "renames": { "composers": { "Chopin": "Frédéric Chopin" } },
  "items": [
    { "match": "Fur Elise",
      "set": { "title": "Für Elise", "reference": "WoO 59", "key": "A minor", "genres": ["Classical"] },
      "add": { "tags": ["ABRSM Grade 5"] } },
    { "match": "Kinderszenen › Träumerei", "set": { "reference": "Op. 15 No. 7" } }
  ]
}

• match: a UUID, an exact title, or "Score › Bookmark" (> works too).
• set replaces these fields: title, reference, key, rating (0–5), difficulty (0–3), duration ("m:ss"), composers, genres, tags and labels.
• add and remove edit the list fields.
• renames renames a value everywhere it is used.

What the CSV import cannot do

forScore's CSV format has no columns for these, so the tool lists them under "not in CSV" instead of importing them:

• scores that have bookmarks, and bookmarks themselves: forScore's CSV import does not match existing bookmarks reliably and can delete or duplicate them
• library membership
• composer sort names (sort_names)
• keys with more than 7 sharps or flats
• values containing a comma
• changing PDF file names

Make these changes in forScore itself. Changing a title in forScore can rename the PDF to match.

MCP tools

Every tool's parameters and the full CLI are listed in docs/reference.md, which is generated from the code.

Environment variables:

• FORSCORE_LIBRARY: path to the library database.
• FORSCORE_STATE_DIR: where import CSVs are kept. The default is ~/Library/Application Support/forscore-mcp.
• FORSCORE_BACKUP_DIR: where backups go.

Direct writes (unsupported by forScore)

Can cause crashes, unexpected behaviour or data loss. forScore's developers advise against it. It bypasses forScore's own validation and edits the database and the per-score sync files directly.

For the changes the CSV import cannot make (scores with bookmarks, library membership, composer sort names), the tool can write the database directly. This is off by default. Turn it on with a confirmation phrase:

forscore-mcp direct-writes enable i-understand-this-can-damage-my-library
forscore-mcp direct-writes status
forscore-mcp direct-writes disable

The setting is stored in ~/Library/Application Support/forscore-mcp/config.json and takes effect immediately, including for a running MCP server. Instead, the variable FORSCORE_DIRECT_WRITES=i-understand-this-can-damage-my-library can be set in an MCP client's env configuration.

While it is on:

• A write is only direct when asked for: apply_changeset(..., method="direct") or forscore-mcp apply --direct --yes. Everything else still goes through the CSV import.
• forScore must be quit on the Mac during direct writes, and a backup is made first.
• restore puts a backup back.
• Values nothing uses any more are deleted. forScore hides them anyway, and each device keeps its own list.
• doctor shows that direct writes are on.

No MCP tool can turn direct writes on.

Limitations

• macOS only.
• Early (0.x), tested with forScore 15.2. A forScore update that changes the database layout makes the tool refuse to run until it is updated.
• Setlists are read-only.

Contributing

Issues and pull requests are welcome, including reports from other forScore versions and setups. See CONTRIBUTING.md.

Development:

uv sync
uv run pytest            # tests use a synthetic library, never a real one
uv run ruff check . && uv run ruff format . && uv run ty check

AGENTS.md describes the architecture and rules; docs/schema.md documents what is known about forScore's storage; docs/releasing.md covers releases.

License

PolyForm Noncommercial 1.0.0: free for personal and other non-commercial use, including changing and sharing it. Commercial use requires a separate license; open an issue or contact the author to ask.