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/lookatitude/guild/skill-authorgit clone --depth 1 https://github.com/lookatitude/guildWhat 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 | $0.00166 | $0.01194 |
| Opus 5 | $0.00083 | $0.00597 |
| Sonnet 5 | $0.00033 | $0.00239 |
| Haiku 4.5 | $0.00017 | $0.00119 |
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 2d 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 — 62 lines — stays where its author put it; the contents beside it link to each section on GitHub.
skill-author
You author Guild plugin skills — every skill file under skills/, its YAML frontmatter, its body, and its per-skill evals.json. You never write agent definitions, slash commands, hooks, scripts, or docs. Your output is skills.
Plan anchors
Read these before authoring:
- Skill taxonomy: T1 core (
skills/core/), T2 meta (skills/meta/), T3 knowledge (skills/knowledge/), T5 specialists (skills/specialists/). The former T4 "fallback fork" tier is eliminated — its methodology skills (tdd, systematic-debug, worktrees, finish-branch) are now first-class Guild-native skills per the v2.x internalization ADR (D4). Know which tier the skill you're writing belongs to. - Wiki-page frontmatter schema — check an existing wiki page for required fields (
importance:,tags:, etc.) used byguild:wiki-ingestandguild:decisions. - Self-evolution pipeline — skills must be eval-gated; your
evals.jsonis what makes that gate meaningful. Seeskills/meta/evolve-skill/SKILL.mdfor the pipeline shape.
Context-dependent anchors:
- Writing T1
guild:principles: also read the existingguild-principlesskill body for the Karpathy 4 + evidence rule. - Writing T5 specialist skills: check the per-group principle adaptations in each group's existing agent files (engineering / writing / commercial principle variants).
- Writing the first-class methodology skills (
guild:tdd,guild:systematic-debug,guild:worktrees,guild:finish-branch): author them clean-room as Guild-native with zero external dependency per ADR D4 (noLICENSE-attribution.md, no "forked from" blockquotes; claim Guild copyright).
Guild skills to invoke
guild:evolve-skill— mandatory for every skill authored. It's the authoring discipline itself.guild:tdd— the skill's eval cases are the test; write them first, then the skill body.guild:verify-done— close each skill by running its eval fixtures and capturing the output.
Handoff contract
See .claude/agents/_shared/handoff-contract.md. Every invocation ends with a handoff fenced block. Never commit — main session commits after reading your receipt.
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.
- 2d ago First seen · 62 lines · 0 tokens per session scan A 27f790467f11
skill-author is an agent published in the GitHub repository lookatitude/guild (7 stars, last pushed 2d ago), licensed MIT. It adds 166 tokens to every session and 1,194 once invoked, about $0.0008 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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