Borrowing it
Nothing to install: this file belongs to arcjet/skills. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/arcjet/skills/main/AGENTS.mdgit clone --depth 1 https://github.com/arcjet/skillsWrote 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/instructions/arcjet/skills/agents-md)<a href="https://agentmods.dev/instructions/arcjet/skills/agents-md"><img src="https://agentmods.dev/badge/instructions/arcjet/skills/agents-md/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/instructions/arcjet/skills/agents-md"><img src="https://agentmods.dev/badge/instructions/arcjet/skills/agents-md.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 | $0.00688 | $0.00688 |
| Opus 5.5 | $0.00275 | $0.00275 |
| Sonnet 5.5 | $0.00138 | $0.00138 |
| Haiku 4.5 | $0.00069 | $0.00069 |
Grade A, and why
skills AGENTS.md 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 1mo 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 — 33 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md
Loose lessons learned while using the skill-creator skill (at .agents/skills/skill-creator/). Terse on purpose. Always read .agents/skills/skill-creator/SKILL.md first — this file only supplements it.
Subagent prompts for test runs
- Keep prompts minimal. The prescribed format (
Skill path / Task / Input files / Save outputs to) is enough — don't add framing like "you're running an eval," "report what you did," or environment hints the agent should discover itself (e.g. that the CLI is pre-authenticated). - Don't add restrictions like "don't run the server" or "typechecking optional." Those bias the agent away from the verification step you're trying to measure.
Aggregation gotchas
- The aggregator expects per-run subdirectories:
eval-X/<config>/run-N/grading.json(plustiming.json). If you save outputs ateval-X/<config>/grading.json(norun-N), it picks up nothing and reports 0%. - Config ordering in
benchmark.mdis alphabetical, which meansnew_skill/old_skillandwith_skill/without_skillflip the delta sign. Sanity-check the sign by hand.
Capturing subagent transcripts
- Each
Agenttask writes its JSONL transcript to/tmp/claude-*/-workspaces-*/<session>/tasks/<task_id>.output. Don'tcatorReadit — it's the full transcript and will blow your context. - Do
cpit into the run directory astranscript.jsonlonce the task completes. The viewer also looks fortranscript.mdat the same level.
Eval viewer
- It embeds every file under
outputs/into a single inline<script>. Without an exclude list it'll happily inline 482 MB ofnode_modules, and a stray backtick inside a vendored file crashes the page. The current code excludesnode_modules,__pycache__,.venv,.next,dist,build, lockfiles, etc. — extend that list if a new ecosystem shows up. - Bind to
0.0.0.0(not127.0.0.1) so devcontainer / remote setups can reach it via the forwarded port.
When the same baseline serves multiple iterations
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.
- 1mo ago First seen · 33 lines · 688 tokens per session scan A 6504c220d8dd
skills AGENTS.md is an instructions file published in the GitHub repository arcjet/skills (4 stars, last pushed 20d ago), licensed Apache-2.0. It adds 688 tokens to every session, about $0.0028 per session on Opus 5.5. 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.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
vscode model-prompts.instructions.md
Model-specific prompt authoring and registry guidelines.