THIRI Chord Intelligence
About
Deterministic music-theory engine for AI agents to analyze, resolve, voice, and reharm chords.
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- bluesprince
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- Developer Tools, Other, Media
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Setup
Install THIRI Chord Intelligence in your MCP client (Claude Desktop, Cursor, Windsurf, and others).
Repository: https://github.com/bluesprince/thiri-mcp
Follow the installation instructions in the repository README, then restart your MCP client.
What can you do with THIRI Chord Intelligence MCP?
- Analyze chord structure— Askanalyze_chordto return root, quality, intervals, roman numeral, and harmonic function for any chord in a key.
- Resolve chord notes— Useresolve_chordto get enharmonically correct spellings, frequencies, MIDI values, and scale recommendations.
- Generate instrument voicings— Requestgenerate_voicingwith styles like rootless, shell, or drop-2, and passpreviousNotesfor voice-leading scores.
- Reharmonize progressions— Applyreharmonizewith techniques liketritone_sub,coltrane_changes, orautoto transform chord progressions.
- Conduct a band— Useconduct_bandto translate natural-language directions into instrument lanes and MIDI output.
Give your AI real music theory.THIRI is the deterministicmusic theory MCP server + APIfor AI builders — it lets Claude, Cursor, or anyMCPagentanalyze chords, run roman-numeral analysis, generate voicings, and reharmonize progressionswith answers that arecomputed, not guessed.
LLMs hallucinate music theory: wrong notes, fake roman numerals, voicings that don't voice-lead. THIRI is adeterministicengine (pitch-class-set theory over ℤ/12) behind a hosted API — soC7sus4keeps its suspension,CaugspellsC E G#, and "Coltrane changes on Dm7 G7 Cmaj7" returnsCmaj7 Ab7 Abmaj7 E7, every time.
Downstream of Suno / Udio or any generator?Wrap the output and get a correct chord chart your agent can trust. And unliketonal.jsormusic21, THIRI is hosted and agent-native (no install, any language) — and itreharmonizesandvoice-leads, not just looks chords up.
⭐ If this is useful, star the repo — it helps other musicians and agent builders find it.
👥Join the First 55 AI Music Builders: Want elevated rate limits (300 req/min), direct founder support, and early access to upcoming tools? Join our developer community onSkool — Blues People AI.
- Get a free key atbuild.thiri.ai/developers
- InClaude: Settings →Connectors→Add custom connector→ URLhttps://mcp.thiri.ai/mcp→ paste yoursk_live_key
- Ask Claude:"Reharmonize Dm7 G7 Cmaj7 with Coltrane changes."
That's it — no install, no config file. Builders: full install options (Claude Code, Desktop config, raw HTTP) arebelow.
"Analyze Dm7b5 in C."→iiø7, half-diminished, borrowed predominant, + scale options"What notes are in C7sus4?"→C F G Bb(the suspension survives)"Give me a rootless Cmaj7 voicing, then voice-lead into Dm7."→ voicings + a voice-leading score"Reharmonize Dm7 G7 Cmaj7 with Coltrane changes."→Cmaj7 Ab7 Abmaj7 E7
Runs on thev2 grid engine— correct sus chords, real triads, enharmonic spelling, all altered dominants — with request timeouts, quota reporting, and structured errors.
Conductor & composition companions (Desktop only)
Forhear-itagent loops (conduct → server-side render → WAV through your speakers), add a second local server alongside hosted theory tools:
{ "mcpServers": { "thiri": { "command": "npx", "args": ["-y", "@bluesprincemedia/thiri-mcp"], "env": { "THIRI_API_KEY": "sk_live_your_key" } }, "thiri-conductor": { "command": "npx", "args": ["-y", "@bluesprincemedia/thiri-mcp", "thiri-conductor-mcp"], "env": { "THIRI_API_KEY": "sk_live_your_key" } }, "thiri-composition": { "command": "npx", "args": ["-y", "@bluesprincemedia/thiri-mcp", "thiri-composition-mcp"] } } }
Rendering runsserver-sideas of v0.5.0 — no Csound install needed. Proof:npm run test:conductor· live docs:build.thiri.ai/lab/conductor-mcp·agent recipes.
End-to-end persona for local vibe composition — skill, CLI, and Band dashboard panel:
Dual MCP config above +mapConductResultToStudioModulesafter eachconduct_band. Last CLI render writes~/.thiri/conductor-last.json(local only, not committed).
Flagship agent recipe (analyze → conduct → render → critique)
Paste in order after dual MCP config above:
- Analyze—"Analyze Dm7 G7 Cmaj7 in key C with analyze_chord; summarize roman numerals and tension."
- Conduct—"conduct_band: warm Rhodes pad, walking bass, brush drums, 8 bars medium swing in C."
- Render—"render_audio from the conduct result at tempo 120."
- Critique—"play_audio; critique voice-leading and register balance; suggest one revision."
Full prompts:build.thiri.ai/lab/agent-recipes
Get a free key atbuild.thiri.ai/developers, then pick a path:
Claude Desktop / web / mobile — hosted (one-click custom connector, nothing to install):Settings → Connectors →Add custom connector→ URLhttps://mcp.thiri.ai/mcp→ paste yoursk_live_key on the consent page. Same 5 tools, same key, same quota — no config file, nonpx.
claude mcp add thiri --env THIRI_API_KEY=sk_live_your_key -- npx -y @bluesprincemedia/thiri-mcp
Claude Desktop(claude_desktop_config.json):
{ "mcpServers": { "thiri": { "command": "npx", "args": ["-y", "@bluesprincemedia/thiri-mcp"], "env": { "THIRI_API_KEY": "sk_live_your_key" } } } }
curl -X POST https://chords.thiri.ai/v2/analyze \ -H "Authorization: Bearer YOUR_KEY" -H "content-type: application/json" \ -d '{"chord":"Dm7b5","key":"C"}'
Five endpoints:/v2/analyze,/v2/resolve,/v2/voicing,/v2/reharmonize,/v2/conduct. Seeopenapi.yaml.
npm install && npm run build && npm start
PolyForm Noncommercial 1.0.0— © 2026 Blues Prince Media. Free for personal, research, and noncommercial use; commercial use requires a license (dennison@bluesprincemedia.com). SeeLICENSE. Versions published at or before v0.5.0 remain under the MIT/PolyForm dual license they shipped with.
As of v0.5.0 the composition engine and Csound renderer run server-side behind the hosted API (POST /v2/compose,POST /v2/render); their source no longer ships in this package.
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