chord-info

chord-info is a skill for Claude Code from GuitarAlchemist/ga. It costs 68 tokens per session (1,525 once invoked), scanned A, original, MIT.

A music-theory reference that gives the notes and interval names making up a named chord.

In plain words
What is it for?
Use it to inspect chords such as Cmaj7, F#dim, or Bbm7 and understand their component notes.
Why use it?
It prevents mistakes when checking chord construction, including alternate spellings of the same pitch.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it to inspect chords such as Cmaj7, F#dim, or Bbm7 and understand their component notes.

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Install with agentmods
npx agentmods add skills/guitaralchemist/ga/chord-info
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.

Any agent
npx skills add GuitarAlchemist/ga --skill chord-info
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.

agentmods badge for chord-info

README.md
[![agentmods](https://agentmods.dev/badge/skills/guitaralchemist/ga/chord-info/github.svg)](https://agentmods.dev/skills/guitaralchemist/ga/chord-info)
Your own site
<a href="https://agentmods.dev/skills/guitaralchemist/ga/chord-info"><img src="https://agentmods.dev/badge/skills/guitaralchemist/ga/chord-info/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.

agentmods 80×15 button for chord-info

Your own site · 80×15
<a href="https://agentmods.dev/skills/guitaralchemist/ga/chord-info"><img src="https://agentmods.dev/badge/skills/guitaralchemist/ga/chord-info.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 68 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,525 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00068 $0.01525
Opus 5 $0.00034 $0.00763
Sonnet 5 $0.00014 $0.00305
Haiku 4.5 $0.00007 $0.00153

Measured 9d ago against content hash 87bb36aba555, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

chord-info 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 9d 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.

skills/chord-info/SKILL.md · 109 lines

How it starts

The opening of the file, as written. The whole thing — 109 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Notes of a Chord

When a user asks for the notes / intervals / construction of a named chord, call the ga_chord_info MCP tool. Do NOT recall the notes from training knowledge — different sources spell the same chord differently (Bbm = Bb-Db-F vs Bb-C#-F) and the LLM will confidently produce wrong enharmonics for less-common keys.

Calling the tool

The tool takes one argument:

  • chordSymbol — string, e.g. "C", "Cm", "Cmaj7", "F#dim", "Bbm7". Case-insensitive root letter; quality suffix uses the standard short forms below.

It returns a structured result:

  • Symbol — chord symbol echoed back.
  • Root — root note in canonical case (e.g. "F#").
  • Quality — long form: "major", "minor", "diminished", "augmented", "dominant 7", "major 7", "minor 7", "diminished 7", "half-diminished".
  • Notes — array of chord tones in ascending order.
  • Intervals — interval names for each note (e.g. ["root", "major third", "perfect fifth"]).
  • Error — non-null only when the input could not be parsed.

Supported quality suffixes

Symbol form Quality returned
C, Cmaj, CM "major"
Cm, Cmin "minor"
Cdim "diminished"
Caug "augmented"
C7, Cdom7 "dominant 7"
Cmaj7, CM7 "major 7"
Cm7, Cmin7 "minor 7"
Cdim7 "diminished 7"
Cm7b5, Cmin7b5 "half-diminished"

Mapping user phrasings to arguments

  • "What is a C major chord?"chordSymbol="C" (or "Cmaj").
  • "What notes are in Dm7?"chordSymbol="Dm7".
  • "Spell a B7 chord"chordSymbol="B7".
  • "Notes in an F minor chord"chordSymbol="Fm".
  • "What's in a Cmaj7?"chordSymbol="Cmaj7".
  • "Spell a B half-diminished"chordSymbol="Bm7b5".
  • "What's a C diminished 7th?"chordSymbol="Cdim7".

Phrasing the answer

Use the Notes array verbatim, joined with (en-dash) or commas. Mention the Quality and the Intervals for educational color. Example:

Read the full file on GitHub · 109 lines

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.

  1. 9d ago First seen · 109 lines · 68 tokens per session scan A 87bb36aba555

Subscribe to this mod's changes

chord-info is a skill published in the GitHub repository GuitarAlchemist/ga (2 stars, last pushed today), licensed MIT. It adds 68 tokens to every session and 1,525 once invoked, about $0.0003 per session on Opus 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 2026-09-03.

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