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 ronmkr/PromptBook --skill example-skillgit clone --depth 1 https://github.com/ronmkr/PromptBookWrote 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/ronmkr/promptbook/example-skill)<a href="https://agentmods.dev/skills/ronmkr/promptbook/example-skill"><img src="https://agentmods.dev/badge/skills/ronmkr/promptbook/example-skill.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 5.1 | $0.00049 | $0.00567 |
| Opus 5 | $0.00024 | $0.00283 |
| Sonnet 5 | $0.00010 | $0.00113 |
| Haiku 4.5 | $0.00005 | $0.00057 |
Grade A, and why
example-skill 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 6d 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.
This is a copy
83% identical to example-skill — 10 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Example Skill
This skill demonstrates the structure and format for Antigravity plugin skills.
Overview
Skills are model-invoked capabilities that Gemini autonomously uses based on task context. Unlike commands (user-invoked) or agents (spawned by Gemini), skills provide contextual guidance that Gemini incorporates into its responses.
When This Skill Applies
This skill activates when the user's request involves:
- Creating or understanding plugin skills
- Skill template or reference needs
- Skill development patterns
Skill Structure
Required Files
skills/
└── skill-name/
└── SKILL.md # Main skill definition (required)
Optional Supporting Files
skills/
└── skill-name/
├── SKILL.md # Main skill definition
├── README.md # Additional documentation
├── references/ # Reference materials
│ └── patterns.md
├── examples/ # Example files
│ └── sample.md
└── scripts/ # Helper scripts
└── helper.sh
Frontmatter Options
Skills support these frontmatter fields:
- name (required): Skill identifier
- description (required): Trigger conditions - describe when Gemini should use this skill
- version (optional): Semantic version number
- license (optional): License information or reference
Writing Effective Descriptions
The description field is crucial - it tells Gemini when to invoke the skill.
Good description patterns:
description: This skill should be used when the user asks to "specific phrase", "another phrase", mentions "keyword", or discusses topic-area.
Include:
- Specific trigger phrases users might say
- Keywords that indicate relevance
- Topic areas the skill covers
Skill Content Guidelines
- Clear purpose: State what the skill helps with
- When to use: Define activation conditions
- Structured guidance: Organize information logically
- Actionable instructions: Provide concrete steps
- Examples: Include practical examples when helpful
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.
- 6d ago First seen · 85 lines · 49 tokens per session scan A 2184005468ac
example-skill is a skill published in the GitHub repository ronmkr/PromptBook (2 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 49 tokens to every session and 567 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 83% identical to example-skill, differing in 10 lines, and is treated as a copy.
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