THIRI · Chord Intelligence

The deterministic music-intelligence layer for AI.

Generative audio has ears. THIRI is the brain. A computed — not generated harmony engine that parses, spells, voices, and reharmonizes any chord progression — behind a REST API and an MCP server. Correct by construction, on every call.

The control seam

Diffusion models generate texture; they can't reliably control harmony — the changes drift, voice-leading blurs, and "make it Coltrane changes" gets ignored. Harmony is a symbolic problem. THIRI solves it deterministically and hands your model a correct harmonic plan to condition on.

Your model's ears, THIRI's brain. ~40 ms per call. No GPU. Same input → same correct answer, every time.

🎷 Hear it live → future.thiri.ai

Four capabilities, one engine

analyze

chord → quality, intervals, roman numeral, harmonic function

resolve

chord → spelled notes, frequencies, MIDI, scale recommendations

voice

instrument-ready voicings with a voice-leading score

reharmonize

8 techniques — tritone sub, Coltrane changes, backdoor, and more

Built to sit inside

• AI audio platforms — the harmonic-conditioning layer for generative models.
• DAWs & plugin makers — correct theory for suggestion, analysis, and assistive features.
• Music-education platforms — a provably-correct answer key for theory, ear, and comping.
• Agent builders — an MCP-native tool so any assistant can reason about harmony.

Why THIRI, not a model

✓ Deterministic & conformance-tested — answers are computed; a public correctness suite proves it.
✓ The only reharmonization engine — 8 jazz techniques in one call. No model does this reliably.
✓ Voice-leading scoring — objective feedback on how chords connect.
✓ Agent-native — live MCP server; drop it into Claude, Cursor, or your own agent today.
✓ One engine, any surface — same correctness over REST, MCP, and embeddable clients.

Partner with THIRI

Building something that needs to understand harmony? Let's talk about the integration.

THIRI is the intelligence layer of Blues Prince Media's music stack. WoodShed (player tools) and Cadence (rights & settlement) build on the same foundation.