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 agents/guitaralchemist/ga/skill-authorgit clone --depth 1 https://github.com/GuitarAlchemist/gaWrote 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/agents/guitaralchemist/ga/skill-author)<a href="https://agentmods.dev/agents/guitaralchemist/ga/skill-author"><img src="https://agentmods.dev/badge/agents/guitaralchemist/ga/skill-author.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 | $0.00070 | $0.01149 |
| Opus 5 | $0.00035 | $0.00575 |
| Sonnet 5 | $0.00014 | $0.00230 |
| Haiku 4.5 | $0.00007 | $0.00115 |
Grade A, and why
skill-author 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 3d 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 — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.
skill-author — draft a new chatbot skill
Generate a fresh SKILL.md under skills-dev/<name>/ so the user can
start iterating immediately. The output must satisfy GA's
SKILL.md schema so the
chatbot's FileBasedSkillsProvider picks it up via live-reload, and
Claude Code can also load it as a plugin skill.
Inputs the user provides
- A short name (kebab-case, like
progression-moodorchord-info). - A one-paragraph description of what the skill should do.
- Optional: example user prompts that should trigger it.
- Optional: classification — catalog (deterministic lookup, no LLM per call), computation (calls an MCP tool deterministically), or hybrid (LLM synthesizes over a deterministic substrate).
Pre-flight checks (refuse if these fail)
- No name collision: glob
skills/<name>/SKILL.mdandskills-dev/<name>/SKILL.md. If either exists, refuse and tell the user to either pick a different name OR explicitly invoke the graduator/redrafter pattern (move existing to drafts first). - Name is kebab-case:
^[a-z][a-z0-9-]*$. Reject snake_case, PascalCase, spaces. - Description is non-empty and contains at least one usage hint like "use when" or "when the user asks". The description is what the orchestrator's intent router (and Claude Code's slash-command matcher) score against — vague descriptions misroute.
Output template
---
name: <name>
description: |
<one paragraph: what the skill returns, when to use it, what
evidence kind it produces. Include 2-3 user-prompt fragments
the orchestrator should match against.>
triggers:
- "<trigger phrase 1>"
- "<trigger phrase 2>"
- "<trigger phrase 3>"
license: internal
compatibility:
agent-framework: ">=1.0.0-preview"
metadata:
authoring-style: <deterministic-catalog | mcp-tool-driven | hybrid-llm>
origin: "drafted by skill-author agent on <ISO date>"
evidence-kinds:
- <catalog_lookup | mcp_tool_call | llm_synthesis>
---
# <Skill title>
## When the chatbot dispatches to this skill
<Concrete user-prompt examples — at least 3. The orchestrator's intent
router compares user messages against THIS body as well as the
description, so concrete examples here improve routing precision.>
## What the skill returns
<Output structure: sections, fields, formats. Include a short example
output if the format is non-obvious.>
## How the skill computes
<Reference the implementation: an `IOrchestratorSkill` class for
catalog skills, an MCP tool name for tool-driven skills, or "LLM
synthesis grounded on <X>" for hybrid skills. State whether the
behaviour is fully deterministic or whether the LLM is in the path.>
## Refuse to invent
<List the things the skill MUST NOT hallucinate — chord voicings
outside the catalog, scale memberships, set-class numbers, etc. The
chatbot's groundedness validator gates on these.>
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.
- 3d ago First seen · 123 lines · 70 tokens per session scan A 87e35fa55a2d
skill-author is an agent published in the GitHub repository GuitarAlchemist/ga (2 stars, last pushed today), licensed MIT. It adds 70 tokens to every session and 1,149 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 2026-08-31.
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