22 Ways to Build with the THIRI MCP Server

The release of the THIRI Model Context Protocol (MCP) server has unlocked a new paradigm for developers, composers, and AI engineers. By wrapping music theory math and chord spelling engines into a standardized interface, any LLM or AI agent can now query music theory natively.

Here is a developer’s blueprint showcasing 22 creative applications, system prompts, and configuration templates you can copy and build today.

🌐 1. Interactive UI Widgets & Web Apps

#1. Helix (3D AI Arpeggiator)

An interactive 3D perspective arpeggiator that maps chord progressions onto an octave lattice, rendering note paths and trailing spectrogram heatmaps while running real-time API logs.

#2. Reharmonization Sandbox (VibeCheck)

A drag-and-drop song grid where clicking on a chord (e.g., ii-V-I) queries /v2/reharmonize to suggest tritone substitutions, secondary dominants, and modal mixtures.

#3. Voicing Style Keyboard (Voicify)

A piano roll widget showing piano key distributions for different keyboard styles (e.g., Rootless Jazz, Open Gospel, Close-Position Clusters) queried via /v2/voicing.

#4. Circle of Fifths Modulation Mapper

A visualization mapping optimal transition paths when modulating from one distant key center to another.

#5. MIDI Real-time Lead Sheet Companion

A web widget listening to MIDI keyboards, resolving chord pitch-classes in real-time, and overlaying Roman numeral analysis.

#6. Csound Synthesis Tension Mapper

A Web Audio synthesizer mapping filter cutoffs and LFO speeds to /v2/analyze tension coefficients, making the synth grow brighter as tension increases.

🤖 2. AI Agent Skills & Workflows

#7. MIDI Chord Analyzer Skill

An agent tool that parses MIDI files, groups note clusters, and prints clean lead-sheet chords.

#8. Melodic Harmonizer Skill

A tool that takes a single melody line (MIDI/XML) and writes a 4-part backing harmony avoiding voice-leading errors.

#9. Guitar Voicing Fretboard Adapter

Translates keyboard voicings into physical guitar fingerings, adjusting for fret range and open strings.

#10. Groove Scheduler Skill

Alters the drum pattern’s syncopation and swing based on the current harmonic tension coefficient.

#11. Automated Lo-Fi Reharmonizer Bot

An autonomous n8n workflow that monitors song lists, reharmonizes chord charts into a lo-fi aesthetic, and exports the final MIDI.

#12. Sheet Music OCR Verifier

Scans printed lead sheets via OCR, resolves pitches via /v2/resolve, and flags incorrect chord symbols.

💬 3. Copyable System Prompts & AI Templates

#13. Copyable Prompt: “Jazz Harmony Advisor”

Copy and paste this system prompt into Claude or Claude Code to configure it as a professional jazz theory tutor:

You are a master jazz theory consultant. Your task is to evaluate the user's chord progression and suggest advanced substitutions using the THIRI MCP server. 

When the user gives you a progression:
1. Run 'analyze_chord' on each chord to evaluate tension.
2. Suggest substitutions (such as Tritone Substitutions, Altered Dominants, or Minor Plagal Cadences) for high-tension chords.
3. Spell out the new voicings in pitch classes (0-11).

#14. Copyable Prompt: “Csound Score Compiler”

Instructs the agent to output clean Csound scores (.sco) using resolved pitches:

You are a Csound score compiler. Generate a Csound score block (.sco) based on the user's chord progression.
Use the THIRI 'resolve_chord' tool to get the MIDI numbers, convert them to Csound pitch representation (octave.pitch, e.g., 8.00 for Middle C), and format the score lines.

#15. Lyric-to-Chord Sentiment Planner

Evaluates lyric mood and suggests matches using corresponding tension levels.

#16. Microtonal Tuning Explorer

Translates standard 12-tone output from THIRI into custom temperaments (e.g. 31-EDO).

#17. Co-writing Chatbot Editor

An interactive chatbot helper that suggests chord substitutions while writing song parts.

#18. Film Scoring Tension Planner

Generates cue sheets based on scene metadata, matching harmonic tension with visual climaxes.

💻 4. Developer CLIs & Integrations

#19. CLI Tool: thiri-cli

A simple CLI command to quickly query the server from the terminal.

#20. BigFrames Predictor: theory-mcp-framer

A Python tool using BigFrames to train models on classical datasets to identify voice-leading preference patterns.

#21. Ableton Live Max4Live Connector

A Max4Live patch routing MIDI chords through the local THIRI MCP server to auto-generate voicings.

#22. Solana Cadenza Licensing Sync

Registers licensing splits of generated MIDIs using Solana smart contracts.

⚙️ 5. Copyable Configuration: Claude Desktop

To run the THIRI MCP server inside Claude Desktop, copy this config block directly into your claude_desktop_config.json file:

{
  "mcpServers": {
    "thiri-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "thiri-mcp@latest"
      ],
      "env": {
        "THIRI_API_URL": "https://chords.thiri.ai",
        "THIRI_API_KEY": "sk_live_YOUR_KEY_HERE"
      }
    }
  }
}