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 jrgilbertson/the-rookery --skill creating-portable-skillsgit clone --depth 1 https://github.com/jrgilbertson/the-rookeryWrote 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/jrgilbertson/the-rookery/creating-portable-skills)<a href="https://agentmods.dev/skills/jrgilbertson/the-rookery/creating-portable-skills"><img src="https://agentmods.dev/badge/skills/jrgilbertson/the-rookery/creating-portable-skills/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/jrgilbertson/the-rookery/creating-portable-skills"><img src="https://agentmods.dev/badge/skills/jrgilbertson/the-rookery/creating-portable-skills.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00073 | $0.02414 |
| Opus 5 | $0.00036 | $0.01207 |
| Sonnet 5 | $0.00015 | $0.00483 |
| Haiku 4.5 | $0.00007 | $0.00241 |
Grade A, and why
creating-portable-skills 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 — 111 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Creating Skills
Create, revise, migrate, or audit a skill from its intent, required outcome, and only the hard constraints that define acceptable completion or remain under user authority. The result is either a prioritized read-only audit or a self-contained skill package with structural validation, appropriately scoped behavioral evidence, and separate trigger and installation checks.
Skills produced here follow the Agent Skills format: a directory with a SKILL.md (frontmatter plus body) and optional references/, assets/, and scripts/. Canonical frontmatter uses only name, description, license, compatibility, and metadata. Read references/portability.md when authoring frontmatter, choosing an install location, or making a harness-specific claim.
An independent reviewer must not have participated in the authoring discussion or produced the artifact under review. One independent grader inspects each matched case; a different fresh-context reviewer performs the final package review. If the current environment cannot start those independent contexts, prepare a self-contained handoff for a separate session and keep the affected grade or review unverified until that session completes it. Do not substitute the author's own review.
Workflow
Creating a new skill starts at step 1. Auditing, updating, or migrating an existing skill starts at step 0. A read-only audit ends at step 0; approved changes continue through the remaining workflow.
0. Audit an existing skill
Have a separate fresh-context agent that has not participated in the current authoring work read the whole package and the host repository's instructions. Give it the skill, the review checklist, and the stated intent without the author's conclusions. Have it apply references/review-checklist.md top to bottom, then present a prioritized fix list where each item names the problem, impact, and change risk.
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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 Changed · +2 lines · +18 tokens per session 407e3b8894e7
- 7d ago Changed 8eac4b6902ee
- 12d ago First seen · 109 lines · 55 tokens per session scan A 1146b6de5dc6
creating-portable-skills is a skill published in the GitHub repository jrgilbertson/the-rookery (5 stars, last pushed today), licensed MIT. It adds 73 tokens to every session and 2,414 once invoked, about $0.0004 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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