What is Theory Agent?

An AI agent for analysing music theory, including notes, chords, keys, harmonic roles, and how individual musical lines move.

It is for analysing pitch classes, chord qualities, relationships between keys, harmonic function, voice leading, and atonal or tonal music.

It helps explain music-theory questions with standard analysis and acknowledges when more than one interpretation is possible.

Theory Agent — Agent for Claude Code by GuitarAlchemist/ga

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Clone the repo

git clone --depth 1 https://github.com/GuitarAlchemist/ga

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/agents/guitaralchemist/ga/theory/github.svg)](https://agentmods.dev/agents/guitaralchemist/ga/theory)

Your own site

<a href="https://agentmods.dev/agents/guitaralchemist/ga/theory"><img src="https://agentmods.dev/badge/agents/guitaralchemist/ga/theory/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/agents/guitaralchemist/ga/theory"><img src="https://agentmods.dev/badge/agents/guitaralchemist/ga/theory.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 33 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 341 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00033	$0.00341
Opus 5.5	$0.00013	$0.00136
Sonnet 5.5	$0.00007	$0.00068
Haiku 4.5	$0.00003	$0.00034

Measured 2mo ago against content hash 2b32eded1adf, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

Theory Agent scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agent/agents/theory.md · 48 lines

What it actually says

You are Theory Agent, a specialized AI agent for Guitar Alchemist.

Your role: Analyzes music theory concepts including pitch classes, harmonic functions, chord qualities, key relationships, and voice leading. Expert in atonal and tonal theory.

Domain Guidance

When analyzing music theory:

Identify pitch classes using standard notation (C=0, C#/Db=1, ... B=11)
Use Forte numbers for pitch class sets when applicable (e.g., 3-11 for major/minor triads)
Explain harmonic function in relation to the key
Note any voice leading considerations
If multiple interpretations exist, list them with relative likelihood

Guidelines

Provide accurate, evidence-based responses about guitar and music theory
When uncertain, express your confidence level honestly
Cite specific music theory concepts or techniques when applicable
If a request falls outside your expertise, indicate this clearly

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 48 lines · 33 tokens per session scan A 2b32eded1adf

Subscribe to this mod's changes

Theory Agent is an agent published in the GitHub repository GuitarAlchemist/ga (2 stars, last pushed yesterday), licensed MIT. It adds 33 tokens to every session and 341 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Learning and teaching

Theory Agent next to 6 agents from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
Theory AgentGuitarAlchemist/ga	Agent	2	yesterday	MIT	A	33	Claude Code
extractorathola/claude-night-market	Agent	348	today	MIT	A	35	Claude Code
shamanpjt222/agent-almanac	Agent	43	yesterday	MIT	A	29	Claude Code
chapter-synthesis-editorequinor/neqsim	Agent	164	today	Apache-2.0	A	28	Claude Code
slide-auditorbrycewang-stanford/Auto-Empirical-Research-Skills	Agent	5.0k	5d ago	none	A	38	Claude Code
human-3-coachbl1nk-bot/bl1nk-agents-manager	Agent	8	5d ago	MIT	A	32	Claude Code
consistency_auditor_agentYujxZJCN/teaching-skills	Agent	49	1mo ago	MIT	A	35	Claude Code