agent-toolkit AGENTS.md

A shared instruction file for coding agents working in a software repository. It explains how to inspect the codebase, follow its existing structure, build user interfaces, and test changes.

In plain words
What is it for?
Use it when asking an agent to modify an existing repository, especially for frontend work or larger interface changes.
Why use it?
It helps prevent changes that ignore the project’s architecture, design system, accessibility needs, or testing process.

Instructions file for CodexOpenCode

Install

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.

agentmods
npx agentmods add instructions/arnosdeus/agent-toolkit/agents-md
Clone the repo
git clone --depth 1 https://github.com/Arnosdeus/agent-toolkit

Made for: Codex, OpenCode.

Per session 543 This file is loaded in full into every session.
When invoked 543 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00543 $0.00543
Opus 5 $0.00271 $0.00271
Sonnet 5 $0.00109 $0.00109
Haiku 4.5 $0.00054 $0.00054

Measured 2d ago against content hash db6f0e39bb00, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

agent-toolkit 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 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.

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.

AGENTS.md · 76 lines

How it starts

The opening of the file, as written. The whole thing — 76 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Shared Agent Instructions

This file is the portable source of truth for Codex, Cline, and compatible agents. Project-specific instructions and existing design systems take priority.

Repository inspection

Never start coding blindly. Inspect package manifests, project structure, existing components, configuration, tests, documentation, design systems, and all applicable agent instructions. Use the repository's established commands.

Existing architecture

Extend the existing architecture and components whenever practical. Avoid introducing frameworks, dependencies, or abstractions without justification. Keep changes scoped to the request and do not modify unrelated files.

Frontend and UI quality

Follow the project's design system. Use semantic HTML, accessible names, keyboard navigation, visible focus, responsive layouts, and reusable components. Design loading, empty, error, sparse, and dense states. For significant UI work: apply the Vercel Web Interface Guidelines, review the design, verify meaningful flows with Playwright, fix findings, and verify again.

Use image-to-code for screenshot/reference-driven work and preserve working architecture while iterating toward visual fidelity.

Testing

Do not claim a feature works without appropriate verification. Run focused tests, lint/type checks when available, and Playwright for meaningful frontend changes. Report commands and results honestly.

Security

Never commit secrets. Do not add unsafe shell execution, unnecessary network calls, insecure authentication changes, disabled security controls, or unjustified dependency changes.

Git and safety

Do not reset user work, delete unrelated changes, rewrite history, force-push, or modify production repositories while validating this toolkit unless explicitly asked. Review the diff and check for regressions before handoff.

Standard workflow

UNDERSTAND → INSPECT → PLAN → IMPLEMENT → TEST → REVIEW → VERIFY → REPORT

Use relevant skills rather than blindly executing every skill on every task. Use task-skill for implementation, git-review before handoff, and focused review skills when the change warrants them.

Read the full file on GitHub · 76 lines

Changes

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.

  1. 2d ago First seen · 76 lines · 543 tokens per session scan A db6f0e39bb00

Subscribe to this mod's changes

agent-toolkit AGENTS.md is an instructions file published in the GitHub repository Arnosdeus/agent-toolkit (2 stars, last pushed 9d ago), licensed MIT. It adds 543 tokens to every session, about $0.0027 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.