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 timwukp/agent-skills-best-practice --skill hello-worldgit clone --depth 1 https://github.com/timwukp/agent-skills-best-practiceWrote 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/timwukp/agent-skills-best-practice/hello-world)<a href="https://agentmods.dev/skills/timwukp/agent-skills-best-practice/hello-world"><img src="https://agentmods.dev/badge/skills/timwukp/agent-skills-best-practice/hello-world/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/timwukp/agent-skills-best-practice/hello-world"><img src="https://agentmods.dev/badge/skills/timwukp/agent-skills-best-practice/hello-world.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 | $0.00040 | $0.00285 |
| Opus 5 | $0.00020 | $0.00143 |
| Sonnet 5 | $0.00008 | $0.00057 |
| Haiku 4.5 | $0.00004 | $0.00028 |
Grade A, and why
hello-world 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 10d 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.
What it actually says
Hello World Skill
A minimal working skill to verify your setup and understand the basic pattern.
Instructions
When triggered, do the following:
- Greet the user and confirm this skill was activated
- Ask for their name if not already provided
- Generate a personalized welcome message
- Explain the three-level progressive disclosure system:
- Level 1: YAML frontmatter (always loaded, ~100 words)
- Level 2: SKILL.md body (loaded when triggered — you're reading it now)
- Level 3: Linked references (loaded as needed)
Example
User says: "Test my skills setup"
Response:
- Confirm the hello-world skill activated successfully
- Greet the user
- Briefly explain what just happened (skill triggering via description match)
Guidelines
- Keep responses concise and friendly
- This skill is for learning — point users to more complex skills as next steps
- Suggest they look at
skills/skills/skill-creator/to build their own
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.
- 10d ago First seen · 41 lines · 40 tokens per session scan A 29b7d3c65272
hello-world is a skill published in the GitHub repository timwukp/agent-skills-best-practice (10 stars, last pushed 3d ago), licensed MIT. It adds 40 tokens to every session and 285 once invoked, about $0.0002 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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