Nashville Charts

What it does

Nashville Charts renders fully interactive chord charts using the Nashville Number System (NNS) — the notation used by professional session musicians where chords are written as scale degrees (1, 4, 5, 6-) rather than letter names. Because numbers are key-agnostic, every chart is instantly transposable. The app lives inside Claude Desktop as a React SPA and gives musicians a complete chart workflow: create, browse, transpose, plan set lists, and analyse medley pairings — all through natural language.

Key features

• Color-coded Chart Viewer — Scale degrees rendered with distinct colors (1=gold, 4=blue, 5=green, 6-=purple, non-diatonic=red) for fast visual scanning. Collapsible sections with performance annotations and monospace chord-over-lyric alignment.
• One-click Transposition — Click any of 12 key buttons to instantly recalculate the full chord map. Includes capo recommendation with open chord shapes (e.g., "Capo fret 2, play G shapes").
• Chart Browser — Searchable, filterable by key, sortable by title/artist/key. Ships with 4 public-domain example charts.
• Medley Analyzer — Scores song pairs across key compatibility, tempo proximity, time signature, and hook similarity. Visual score bars out of 14 with Claude's transition advice.
• Set List Manager — Two-column organizer for moving songs between active set and pool.
• Chart Creation — Generate new NNS charts via natural language, with auto-calculated chord map, capo suggestion, and section scaffolding.

Installation

Claude Desktop

Add to your claude_desktop_config.json:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "nashville-charts": {
      "command": "npx",
      "args": ["-y", "nashville-charts-app", "--stdio"],
      "env": {
        "CHARTS_ROOT": "~/my-charts"
      }
    }
  }
}

Restart Claude Desktop. Try: "Show me Amazing Grace" or "Browse my charts".

Supported hosts

Claude Desktop (confirmed in README). Supports both stdio and StreamableHTTP transports.