Borrowing it
Nothing to install: this file belongs to krokoko/cairn. 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/krokoko/cairn/main/AGENTS.mdgit clone --depth 1 https://github.com/krokoko/cairnWrote 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/krokoko/cairn/agents-md)<a href="https://agentmods.dev/instructions/krokoko/cairn/agents-md"><img src="https://agentmods.dev/badge/instructions/krokoko/cairn/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/krokoko/cairn/agents-md"><img src="https://agentmods.dev/badge/instructions/krokoko/cairn/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 | $0.00283 | $0.00283 |
| Opus 5.5 | $0.00113 | $0.00113 |
| Sonnet 5.5 | $0.00057 | $0.00057 |
| Haiku 4.5 | $0.00028 | $0.00028 |
Grade A, and why
cairn 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 16d 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
Cairn
Plugin marketplace for making codebases ready for autonomous AI development.
Repository layout
plugins/— self-contained plugins (skills/<name>/with nestedreferences/, plushooks/,scripts/, manifests)plugin.jsonat the plugin root is the portable Agent Plugins manifest;.claude-plugin/and.codex-plugin/hold client-specific ones
.claude-plugin/marketplace.json— Claude Code marketplace registry.agents/plugins/marketplace.json— Codex marketplace registry.cursor-plugin/marketplace.json— Cursor marketplace registry (loads the rootplugin.jsonmanifests)schemas/— JSON schemas for manifests and SKILL frontmattertools/— validators and markdownlint custom rulesdocs/DESIGN_GUIDELINES.md— plugin authoring rulesdocs/DEVELOPMENT_GUIDE.md— local development and CI
Before changing plugins
Run mise run build (lint + reference integrity). See CONTRIBUTING.md.
Size limits
SKILL.md: max 400 linesreferences/*.md: max 150 lines each- Split content across reference files when limits are exceeded
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.
- 16d ago Changed · +2 lines · +67 tokens per session 792f9146eb21
- 1mo ago First seen · 24 lines · 216 tokens per session scan A 6531e1699a9c
cairn AGENTS.md is an instructions file published in the GitHub repository krokoko/cairn (18 stars, last pushed 14d ago), licensed Apache-2.0. It adds 283 tokens to every session, about $0.0011 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 2026-08-30.
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).
deno copilot-instructions.md
Copilot instructions for denoland/deno, covering deno development guide for github copilot, network access, high level overview, key directories and key files to understand first.