Harmonic Coordination Theory (HCT) - Specification

The canonical specification for HCT coordination signals and performance parameters.

Overview

Harmonic Coordination Theory (HCT) proposes a musical ontology for multi-agent coordination. Current frameworks (LangGraph, CrewAI, AutoGen) give you orchestration tools but lack a shared language for coordination semantics—timing, quality, intent, and harmony.

HCT fills this gap using musical performance as the ontology: cues, fermatas, tempo, and dissonance become engineering primitives.

The 7 Coordination Signals

Signal	Meaning	Use Case	Musical Origin
CUE	"Your turn—act now"	Task dispatch	Conductor's downbeat
FERMATA	"Hold for approval"	Human-in-the-loop	Sustained note
ATTACCA	"Immediate handoff"	Real-time flows	Seamless movement transition
VAMP	"Loop until ready"	Quality checks	Repeat until cue
CAESURA	"Full stop"	Emergency shutdown	Dramatic silence
TACET	"Stay silent"	Resource conservation	Instrument rests
DOWNBEAT	"Sync point"	Barrier synchronization	Unified entry

Quick Start

Python

from hct_mcp_signals import cue, fermata

# Signal the analyst to start with high urgency
signal = cue("orchestrator", ["analyst"], urgency=9, tempo="presto")

# Hold for human approval before publishing
hold = fermata("report_agent", "Ready for compliance review", hold_type="human")

TypeScript

import { cue, fermata } from '@hct-mcp/signals';

const signal = cue("orchestrator", ["analyst"], { urgency: 9, tempo: "presto" });
const hold = fermata("report_agent", "Ready for review", { holdType: "human" });

Rust

use hct_mcp_signals::{cue, fermata, Urgency};

let signal = cue("orchestrator", &["analyst"], Urgency::Nine, Tempo::Presto);
let hold = fermata("report_agent", "Ready for review", HoldType::Human);

Go

import "github.com/stefanwiest/hct-mcp-signals/go"

signal := cue.Cue("orchestrator", []string{"analyst"}, 9, "presto")
hold := fermata.Fermata("report_agent", "Ready for review", "human")

Installation

# Python
pip install hct-mcp-signals

# Node.js
npm install @hct-mcp/signals

# Rust
cargo add hct-mcp-signals

# Go
go get github.com/stefanwiest/hct-mcp-signals/go