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 agentmods add skills/ako/backing-tracks/btml-generationnpx skills add ako/backing-tracks --skill btml-generationgit clone --depth 1 https://github.com/ako/backing-tracksWrote 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/ako/backing-tracks/btml-generation)<a href="https://agentmods.dev/skills/ako/backing-tracks/btml-generation"><img src="https://agentmods.dev/badge/skills/ako/backing-tracks/btml-generation.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00013 | $0.02170 |
| Opus 5 | $0.00006 | $0.01085 |
| Sonnet 5 | $0.00003 | $0.00434 |
| Haiku 4.5 | $0.00001 | $0.00217 |
Grade A, and why
btml-generation 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 4d 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.
How it starts
The opening of the file, as written. The whole thing — 316 lines — stays where its author put it; the contents beside it link to each section on GitHub.
BTML Generation Skill
Generate BTML (Backing Track Markup Language) files for guitar practice backing tracks.
What is BTML?
BTML is a YAML-based notation for defining complete backing tracks with chords, rhythm patterns, bass lines, drums, and melody. Files use the .btml extension and are played with the backing-tracks CLI.
File Structure
track:
title: "Song Name"
key: C # Musical key (C, G, Am, F#, Bb, etc.)
tempo: 120 # BPM
time_signature: 4/4
style: rock # Genre hint
tuning: standard # Guitar tuning (optional)
capo: 0 # Capo position (optional)
chord_progression:
pattern: "C G Am F" # Space-separated chord symbols
bars_per_chord: 1
repeat: 4
rhythm:
style: eighth # Chord rhythm style
bass:
style: root_fifth
drums:
style: rock_beat
intensity: 0.7
melody:
enabled: true
style: moderate
density: 0.5
scale:
type: pentatonic_minor
Chord Symbols
| Symbol | Type |
|---|---|
C, G, D |
Major triad |
Am, Em, Dm |
Minor triad |
A7, E7, D7 |
Dominant 7th |
Cmaj7, Gmaj7 |
Major 7th |
Am7, Em7 |
Minor 7th |
E9, A9 |
Dominant 9th |
E5, A5 |
Power chord |
Asus4, Dsus2 |
Suspended |
Bb, F#, Eb |
Accidentals |
Am/G, C/E |
Slash chords (bass note) |
C*2, Am*0.5 |
Duration override (bars) |
Genre Guidelines
Blues
track:
key: A
tempo: 80
style: blues
chord_progression:
pattern: "A7 A7 A7 A7 D7 D7 A7 A7 E7 D7 A7 E7" # 12-bar blues
rhythm:
style: shuffle_strum
swing: 0.67
bass:
style: walking
swing: 0.67
drums:
style: blues_shuffle
intensity: 0.7
melody:
style: blues_head
scale:
type: blues
Jazz
track:
key: C
tempo: 140
style: jazz
chord_progression:
pattern: "Dm7 G7 Cmaj7 Cmaj7" # II-V-I
rhythm:
style: stride
swing: 0.67
bass:
style: walking
drums:
style: jazz_swing
intensity: 0.6
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.
- 4d ago First seen · 316 lines · 13 tokens per session scan A 3778dc03749b
btml-generation is a skill published in the GitHub repository ako/backing-tracks (20 stars, last pushed 8mo ago), licensed MIT. It adds 13 tokens to every session and 2,170 once invoked, about $0.0001 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 2026-08-30.
Other skills, from other repositories
general-video
Author or edit a custom HyperFrames composition when no specialized workflow fits, or when BRIEF.md sets flow: companion. Use for longer or multi-scene pieces, brand and sizzle reels, montages, static loops, static title cards, footage remixes, and freeform builds. Use motion-graphics instead for a short unnarrated…
diagnostic-stem-delivery
Audio production with diagnostic analysis, timecode parsing from documents, and verified export workflow.
chengfeng-cut
剪辑中文口播原素材：逐词转录、词典修字出修字表、五轮扫描找口误与重复、汇总表与重复句子表、打开 Studio 让用户复核、复盘沉淀用户偏好与词典。只产出一份已复核的删词账本，不切媒体、不做字幕、不做分镜动画。用户说剪口播、处理口误、生成口播基础素材、继续剪口播，或确认卡回传 action=returncutreview 时使用。不要用于执行物理剪切、导出剪后视频、单独安装、单独打开工作台或口播分镜成片。.
chengfeng-check-updates
剪辑环境的唯一管理者：就绪检查（skills 是否最新 → Runtime 是否配套）、Skills 更新激活、Runtime 安装与体检。用户说检查更新、安装剪辑环境、装播放器、检查剪辑环境、剪辑环境就绪了吗、配置转录凭证时使用；业务 Skill（剪口播/字幕/画面/导出）第 0 步也引用本 Skill 的就绪检查。不用于剪辑、字幕、画面、导出本身或项目数据迁移。.
infographic-template-updater
Update template catalogs and UI prompts after adding new infographic templates (src/templates/.ts), including SKILL.md template list, site gallery template mappings, and the AIPlayground prompt list.
moq
Build live video, audio, and real-time data apps with Media over QUIC (MoQ). Use when adding live streaming, conferencing, voice AI, or real-time pub/sub to an app; when integrating the @moq/ npm packages, moq- Rust crates, or the Python/Kotlin/Swift/Go/C bindings; or when running a moq-relay server or a gateway…