Example: Sheet Music Server

A demo MCP App that renders ABC notation as sheet music with interactive audio playback using the abcjs library.

MCP Client Configuration

Add to your MCP client configuration (stdio transport):

``json
{
"mcpServers": {
"sheet-music": {
"command": "npx",
"args": [
"-y",
"--silent",
"--registry=https://registry.npmjs.org/",
"@modelcontextprotocol/server-sheet-music",
"--stdio"
]
}
}
}
`

$3

To test local modifications, use this configuration (replace ~/code/ext-apps with your clone path):

`json
{
"mcpServers": {
"sheet-music": {
"command": "bash",
"args": [
"-c",
"cd ~/code/ext-apps/examples/sheet-music-server && npm run build >&2 && node dist/index.js --stdio"
]
}
}
}
`

Features

- Audio Playback: Built-in audio player with play/pause and loop controls
- Sheet Music Rendering: Displays ABC notation as properly formatted sheet music

Running

1. Install dependencies:

`bash
npm install
`

2. Build and start the server:

`bash
npm run start:http # for Streamable HTTP transport
# OR
npm run start:stdio # for stdio transport
`

3. View using the basic-host example or another MCP Apps-compatible host.

$3

When calling the play-sheet-music tool, provide ABC notation:

`json
{
"abcNotation": "X:1
T:C Major Scale
M:4/4
L:1/4
K:C
C D E F | G A B c |"
}
`

#### ABC Notation Examples

C Major Scale:

`abc
X:1
T:C Major Scale
M:4/4
L:1/4
K:C
C D E F | G A B c |
`

Twinkle, Twinkle Little Star:

`abc
X:1
T:Twinkle, Twinkle Little Star
M:4/4
L:1/4
K:C
C C G G | A A G2 | F F E E | D D C2 |
G G F F | E E D2 | G G F F | E E D2 |
C C G G | A A G2 | F F E E | D D C2 |
`

Architecture

$3

Exposes a single play-sheet-music tool that accepts:

- abcNotation: ABC notation string to render

The tool validates the ABC notation server-side using the abcjs parser and returns any parse errors. The actual rendering happens client-side when the UI receives the tool input.

$3

- Receives ABC notation via ontoolinput handler
- Uses abcjs for audio playback controls and sheet music rendering (in renderAbc()`)