PyTheory is a Python toolkit for exploring music theory and composing music, with immediate audio playback and visual representations such as guitar tabs and chord diagrams. Musicians and programmers use it to create arrangements across multiple musical systems, instruments, rhythms, and effects. The catalogue add-ons provide agent guidance for working with the project.
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.
npx skills add kennethreitz/pytheory --skill scales-modes-and-tunings-with-pytheorygit clone --depth 1 https://github.com/kennethreitz/pytheoryWrote 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.
[](https://agentmods.dev/skills/kennethreitz/pytheory/scales-modes-and-tunings-with-pytheory)<a href="https://agentmods.dev/skills/kennethreitz/pytheory/scales-modes-and-tunings-with-pytheory"><img src="https://agentmods.dev/badge/skills/kennethreitz/pytheory/scales-modes-and-tunings-with-pytheory/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.
<a href="https://agentmods.dev/skills/kennethreitz/pytheory/scales-modes-and-tunings-with-pytheory"><img src="https://agentmods.dev/badge/skills/kennethreitz/pytheory/scales-modes-and-tunings-with-pytheory.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00153 | $0.01720 |
| Opus 5.5 | $0.00061 | $0.00688 |
| Sonnet 5.5 | $0.00031 | $0.00344 |
| Haiku 4.5 | $0.00015 | $0.00172 |
Grade A, and why
scales-modes-and-tunings-with-pytheory 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- scales-modes-and-tunings-with-pytheory — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 151 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Scales, Modes & Tunings
Scales and modes, the notes/intervals beneath them, and PyTheory's 16 tuning systems.
Scales & modes
from pytheory import TonedScale
ts = TonedScale(tonic="C4", system="western")
ts.scales # ('chromatic','major','minor','dorian','lydian', …)
s = ts["dorian"]
s.note_names # ['C', 'D', 'Eb', 'F', 'G', 'A', 'Bb', 'C']
[str(t) for t in s.tones] # ['C4', 'D4', 'Eb4', 'F4', …]
s.harmonize() # diatonic chords built on each degree
Pentatonic & blues scales live in the
bluessystem, notwestern:TonedScale(tonic="E2", system="blues")["minor pentatonic"](also"major pentatonic","blues","major blues").
Which scale fits these notes?
Scale.recommend ranks scales by how well they contain a set of notes — great
for "what can I solo with here?". Note the import: pytheory.Scale is an alias
for TonedScale, so import the real class from pytheory.scales:
from pytheory.scales import Scale
Scale.recommend("C", "Eb", "G", "Bb", "D", top=3)
# [('C', 'aeolian', 1.0), ('G', 'aeolian', 1.0), ('C', 'dorian', 1.0)]
# -> (tonic, scale_name, fitness 0..1)
Detect the scale of a note set:
TonedScale(tonic="C4", system="western")["major"].detect("C","D","E","F","G","A","B")
# ('C', 'major', 7) -> (tonic, scale, matched-note count)
Tones, intervals, overtones
from pytheory import Tone
Tone.from_string("A4").frequency # 440.0
Tone.from_midi(69) # <Tone A4>
Tone.from_frequency(440.0) # <Tone A4>
Tone.from_string("C4").interval_to(Tone.from_string("G4")) # 'perfect 5th'
Tone.from_string("A2").overtones(4) # [110.0, 220.0, 330.0, 440.0]
[str(t) for t in Tone.from_string("C4").circle_of_fifths()] # ['C4','G4','D5','A5', …]
Twelve-tone rows (serialism)
A ToneRow is an ordering of all 12 pitch classes, each once. From it come
the 48 forms (P/R/I/RI × 12 transpositions) and the row matrix. The
transposition number is the pitch class the form begins on.
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 · 151 lines · 153 tokens per session scan A a77bc681d9e3
scales-modes-and-tunings-with-pytheory is a skill published in the GitHub repository kennethreitz/pytheory (1,658 stars, last pushed 9d ago), licensed MIT. It adds 153 tokens to every session and 1,720 once invoked, about $0.0006 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 2026-08-30.
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