What is AGENT-ZERO AGENTS.md?

A set of instructions for AI-assisted development projects that use an AGENTS.md file. AGENTS.md is a project guide that tells coding tools how to work within a repository.

Use it to guide compatible coding tools through project startup, planning, refactoring, documentation, quality checks, and session handoffs.

It sets rules for reusing existing files, tracking work, loading project memory, and validating changes before creating or changing files.

How msitarzewski/AGENT-ZERO configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to msitarzewski/AGENT-ZERO. 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/msitarzewski/AGENT-ZERO/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/msitarzewski/AGENT-ZERO

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/msitarzewski/agent-zero/agents-md/github.svg)](https://agentmods.dev/instructions/msitarzewski/agent-zero/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/msitarzewski/agent-zero/agents-md"><img src="https://agentmods.dev/badge/instructions/msitarzewski/agent-zero/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/msitarzewski/agent-zero/agents-md"><img src="https://agentmods.dev/badge/instructions/msitarzewski/agent-zero/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 8,524 This file is loaded in full into every session.

When invoked 8,524 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 100% copy Near-identical to another mod 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.

Model	Per session	Once invoked
Fable 5.1	$0.08524	$0.08524
Opus 5.5	$0.03410	$0.03410
Sonnet 5.5	$0.01705	$0.01705
Haiku 4.5	$0.00852	$0.00852

Measured 2mo ago against content hash ff7e125d3d09, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

AGENT-ZERO 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 2mo 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.

Origin

This is a copy

100% identical to agency-agents-app AGENTS.md — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

AGENTS.md · 1,022 lines

How it starts

The opening of the file, as written. The whole thing — 1,022 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

Version: 2.2 (2025-03-04) | Compatibility: Claude, Cursor, Copilot, Cline, Aider, all AGENTS.md-compatible tools Status: Canonical single-file guide for AI-assisted development

Compliance & Core Rules
Session Startup
- Compaction Protocol
Memory Bank
State Machine
Task Contract & Budgets
Quality & Documentation
Example Workflow
Troubleshooting

1. Compliance & Core Rules

Startup Compliance (Output Every Session)

COMPLIANCE CONFIRMED: Reuse over creation

⚠️  GIGO PREVENTION - User Responsibilities:
📋 Clear task objectives | 🔗 Historical context | 🎯 Success criteria
⚙️  Architectural constraints | 🎖️ You lead - clear input = excellent output

[Continue with Memory Bank loading...]

The Four Sacred Rules

Rule	Requirement	Validation
❌ No new files without reuse analysis	Search codebase, reference files that cannot be extended, provide exhaustive justification	Before creating: "Analyzed X, Y, Z. Cannot extend because [technical reason]"
❌ No rewrites when refactoring possible	Prefer incremental improvements, justify why refactoring won't work	"Refactoring X impossible because [specific limitation]"
❌ No generic advice	Cite `file:line`, show concrete integration points, include migration strategies	Every suggestion includes `file:line` citation
❌ No ignoring existing architecture	Load patterns before changes, extend existing services/components, consolidate duplicates	"Extends existing pattern at `file:line`"

Reuse Validation Checklist (Before Creating Files)

- [ ] Searched: [search terms] → found: [list files]
- [ ] Analyzed extension:
  - [ ] `existing/file1.ext` - Cannot extend: [specific technical reason]
  - [ ] `existing/file2.ext` - Cannot extend: [specific technical reason]
- [ ] Checked patterns: `systemPatterns.md#[section]`
- [ ] Justification: New file needed because [exhaustive reasoning]

Read the full file on GitHub · 1,022 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.

2mo ago First seen · 1,022 lines · 8,524 tokens per session scan A ff7e125d3d09

Subscribe to this mod's changes

AGENT-ZERO AGENTS.md is an instructions file published in the GitHub repository msitarzewski/AGENT-ZERO (290 stars, last pushed 8mo ago), licensed Unlicense. It adds 8,524 tokens to every session, about $0.0341 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to agency-agents-app AGENTS.md, differing in 0 lines, and is treated as a copy.

AGENT-ZERO AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
AGENT-ZERO AGENTS.mdmsitarzewski/AGENT-ZERO	Instructions file	290	8mo ago	Unlicense	A	8,524	Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	today	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

AGENT-ZERO: Instructions file for Codex