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 agentmods add instructions/existential-birds/beagle/agents-mdgit clone --depth 1 https://github.com/existential-birds/beagleWhat 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 | $0.01963 | $0.01963 |
| Opus 5 | $0.00981 | $0.00981 |
| Sonnet 5 | $0.00393 | $0.00393 |
| Haiku 4.5 | $0.00196 | $0.00196 |
Grade B, and why
beagle AGENTS.md scanned grade B with 1 finding 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 2d 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.
Reads agent configuration directoriesmediumAgent snooping
.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.
# In Claude Code settings (~/.claude/settings.json) Copies of this mod
1 near-identical copy found in the catalogue:
- beagle CLAUDE.md — 88% identical, 28 lines differ
How it starts
The opening of the file, as written. The whole thing — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md
This file provides guidance to Codex when working with code in this repository.
What This Is
Beagle is a Claude Code plugin marketplace providing framework-aware code review skills and verification workflows for pre-push reviews and GitHub bot feedback handling. It contains 10 focused plugins with 132 skills.
Marketplace Architecture
beagle/
├── .claude-plugin/
│ └── marketplace.json # Marketplace manifest (10 plugins)
└── plugins/
├── beagle-core/ # Shared workflows, verification, git workflows, skill tooling (19 skills)
├── beagle-python/ # Python, FastAPI, SQLAlchemy, PostgreSQL, pytest (7 skills)
├── beagle-go/ # Go, BubbleTea, Wish SSH, Prometheus (13 skills)
├── beagle-elixir/ # Elixir, Phoenix, LiveView, ExUnit, ExDoc (11 skills)
├── beagle-ios/ # Swift, SwiftUI, SwiftData, iOS frameworks (16 skills)
├── beagle-react/ # React, React Flow, shadcn/ui, Tailwind, Vitest, Remix v2 (28 skills)
├── beagle-rust/ # Rust, tokio, axum, sqlx, serde (12 skills)
├── beagle-ai/ # Pydantic AI, LangGraph, DeepAgents, Vercel AI SDK (deprecated)
├── beagle-docs/ # Documentation quality, AI writing detection (10 skills)
├── beagle-analysis/ # Brainstorming, ADRs, strategy, LLM-as-judge, spec resolution, PRFAQ filter (14 skills)
└── beagle-testing/ # Test plan generation and execution (2 skills)
Each active plugin is a directory under plugins/ with its own README.md and skills/ directory. The marketplace manifest at .claude-plugin/marketplace.json is the only plugin manifest; individual plugin directories do not have plugin.json files.
Local Development
Test the marketplace during development:
# In Claude Code settings (~/.claude/settings.json)
{
"plugins": ["/path/to/your/beagle"]
}
Restart Claude Code after changes to reload. Skills are discovered from plugin skills/ directories and trigger keywords in skill frontmatter. Codex users can install the same skills by linking active skill directories into ~/.agents/skills/ (see .codex/INSTALL.md).
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.
- 2d ago First seen · 130 lines · 1,963 tokens per session scan B b07d8ec6deb5
beagle AGENTS.md is an instructions file published in the GitHub repository existential-birds/beagle (79 stars, last pushed 23d ago), licensed Apache-2.0. It adds 1,963 tokens to every session, about $0.0098 per session on Opus 5. A static security scan graded it B with 1 finding (reads agent configuration directories). 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).
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
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 oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).
next.js AGENTS.md
Instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.