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rules-for-ai: Instructions file for Codex

AGENTS.md

rules-for-ai AGENTS.md is an instructions file for Codex, OpenCode from hashiiiii/rules-for-ai. It costs 478 tokens per session, scanned A, original, MIT.

A set of instructions for AI coding agents and contributors covering coding habits, language rules, Git, issues, pull requests, tests, and project instruction files.

In plain words
What is it for?
Use it to guide coding tasks, comments, tests, Git work, issue handling, and pull-request work in repositories that follow these rules.
Why use it?
It gives agents consistent rules for making changes and explains which project or locale instructions take priority.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: reads $CODEX_HOME, but also the file is AGENTS.md. Also seen: mentions CLAUDE.md; mentions AGENTS.md; mentions Codex.

This is hashiiiii/rules-for-ai's own configuration. It tells Codex and OpenCode how to work on rules-for-ai itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything rules-for-ai configures →

not rated 10repo changed 1mo ago A scan 478 tokens original MIT
View source ↗ hashiiiii/rules-for-ai
Reuse

Borrowing it

Nothing to install: this file belongs to hashiiiii/rules-for-ai. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/hashiiiii/rules-for-ai/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/hashiiiii/rules-for-ai

Made for: Codex, OpenCode.

Wrote 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.

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README.md
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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.

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Per session 478 This file is loaded in full into every session.
When invoked 478 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00478 $0.00478
Opus 5.5 $0.00191 $0.00191
Sonnet 5.5 $0.00096 $0.00096
Haiku 4.5 $0.00048 $0.00048

Measured 1mo ago against content hash 95541840493e, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

rules-for-ai 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.

AGENTS.md · 51 lines

What it actually says

AGENTS

  • Do not optimize too early
  • If a task causes difficulty, do it more frequently
  • Correct small defects before they become larger defects
  • Never compromise
  • Never assume intentions that the user did not state
  • Insert a half-width space between full-width and half-width characters
  • Do not use emoji
  • Prioritize comments in tests
  • Write comments that explain the reason
  • Do not write comments that only explain the action
  • Never use mocks or stubs

Language

  • Project instructions (CLAUDE.md / AGENTS.md) take precedence over resolved locale keys
  • If the context contains resolved locale keys, use them
  • If the context does not contain resolved locale keys, read the first existing locale file in this order:
    1. <absolute-git-dir>/rules-for-ai/LOCALE.md
    2. <repo>/.rules-for-ai/LOCALE.md
    3. ~/.config/rules-for-ai/LOCALE.md
    4. Bundled LOCALE.default.md in one of these locations:
      • $CODEX_HOME/rules-for-ai/ for Codex user installations
      • <repo>/.agents/rules-for-ai/ for Codex project and local installations
      • <repo>/.cursor/rules-for-ai/ for Cursor project and local installations
      • The plugin root for other installations
  • Get <absolute-git-dir> with git rev-parse --absolute-git-dir
  • If no locale file exists, use en_US for all keys

Writing

  • Before you write, edit, or review English prose, always read and apply the hashiiiii-write-en skill.
  • Before you write, edit, or review Japanese prose, always read and apply the hashiiiii-write-ja skill.

Git

  • Use the hashiiiii-git skill for Git operations

Issues

  • Use the hashiiiii-issues skill for GitHub issue operations

Pull Requests

  • Use the hashiiiii-pull-request skill for GitHub pull request operations

Images

  • Use the hashiiiii-images skill to create image assets (logos, icons, favicons, and header images)
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. 1mo ago Changed · +5 lines · +55 tokens per session 95541840493e
  2. 1mo ago First seen · 46 lines · 423 tokens per session scan A 7a3baf142b92

Subscribe to this mod's changes

rules-for-ai AGENTS.md is an instructions file published in the GitHub repository hashiiiii/rules-for-ai (10 stars, last pushed 2d ago), licensed MIT. It adds 478 tokens to every session, about $0.0019 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.

Building agentsClaude Codeagentcursor-agentcursor-iderulesskills
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