Borrowing it
Nothing to install: this file belongs to astronomer/agents. 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/astronomer/agents/main/AGENTS.mdgit clone --depth 1 https://github.com/astronomer/agentsWrote 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/astronomer/agents/agents-md)<a href="https://agentmods.dev/instructions/astronomer/agents/agents-md"><img src="https://agentmods.dev/badge/instructions/astronomer/agents/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/astronomer/agents/agents-md"><img src="https://agentmods.dev/badge/instructions/astronomer/agents/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 | $0.00787 | $0.00787 |
| Opus 5.5 | $0.00315 | $0.00315 |
| Sonnet 5.5 | $0.00157 | $0.00157 |
| Haiku 4.5 | $0.00079 | $0.00079 |
Grade A, and why
agents 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 — 89 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Table of Contents generated with DocToc
Claude Code Plugin Development
Plugin Structure
project-root/
├── .claude-plugin/
│ ├── marketplace.json # Marketplace catalog (strict: false)
│ └── plugin.json # Plugin manifest with hooks
└── skills/ # Skills (auto-discovered)
└── skill-name/
├── SKILL.md # Skill with YAML frontmatter
└── hooks/ # Hook scripts (co-located with skill)
└── *.sh
Installing the Plugin
# Add the marketplace (from repo root)
claude plugin marketplace add astronomer/agents
# Install the plugin
claude plugin install astronomer-data@astronomer
# Or test locally (session only)
claude --plugin-dir .
After adding skills or making changes, reinstall the plugin:
claude plugin uninstall astronomer-data@astronomer && claude plugin marketplace update && claude plugin install astronomer-data@astronomer
Skills
Skills are markdown files with YAML frontmatter in skills/<name>/SKILL.md:
---
name: skill-name
description: When to use this skill (Claude uses this to decide when to invoke it)
---
# Skill content here...
- Skills are auto-discovered from the
skills/directory - Claude invokes skills automatically based on the description matching user requests
- Users can also invoke directly with
/plugin-name:skill-name(e.g.,/astronomer-data:authoring-dags)
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 · 89 lines · 787 tokens per session scan A ec6202bb5de4
agents AGENTS.md is an instructions file published in the GitHub repository astronomer/agents (453 stars, last pushed 2d ago), licensed Apache-2.0. It adds 787 tokens to every session, about $0.0031 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.
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.
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).