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codex-proof: Instructions file for Codex

AGENTS.md

codex-proof AGENTS.md is an instructions file for Codex, OpenCode from serein-nyx/codex-proof. It costs 163 tokens per session, scanned A, original, MIT.

Repository instructions for codex-proof, a project that records evidence about software work. They define supported systems, security limits, testing requirements, and how completion claims must be reported.

In plain words
What is it for?
Use them when modifying codex-proof to inspect existing changes, update tests, run its validator and test suite, exercise its command-line entry point, and report observable results.
Why use it?
They give an agent clear rules for making changes and checking its work in that repository. They also prevent credentials or unsupported claims from entering the evidence.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md. Also seen: mentions Codex.

This is serein-nyx/codex-proof's own configuration. It tells Codex and OpenCode how to work on codex-proof 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 codex-proof configures →

not rated 11repo 2mo ago A scan 163 tokens original MIT
View source ↗ serein-nyx/codex-proof
Reuse

Borrowing it

Nothing to install: this file belongs to serein-nyx/codex-proof. 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/serein-nyx/codex-proof/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/serein-nyx/codex-proof

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.

agentmods badge for codex-proof AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/serein-nyx/codex-proof/agents-md/github.svg)](https://agentmods.dev/instructions/serein-nyx/codex-proof/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/serein-nyx/codex-proof/agents-md"><img src="https://agentmods.dev/badge/instructions/serein-nyx/codex-proof/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.

agentmods 80×15 button for codex-proof AGENTS.md

Your own site · 80×15
<a href="https://agentmods.dev/instructions/serein-nyx/codex-proof/agents-md"><img src="https://agentmods.dev/badge/instructions/serein-nyx/codex-proof/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 163 This file is loaded in full into every session.
When invoked 163 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 $0.00163 $0.00163
Opus 5.5 $0.00065 $0.00065
Sonnet 5.5 $0.00033 $0.00033
Haiku 4.5 $0.00016 $0.00016

Measured 2mo ago against content hash 3c14e9ef843d, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

codex-proof 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.

AGENTS.md · 23 lines

What it actually says

Repository instructions

Scope

  • Keep codex-proof dependency-free at runtime.
  • Support Windows, macOS, and Linux with Python 3.11 or newer.
  • Preserve the evidence schema unless a versioned migration is included.
  • Never record environment variables or unredacted credentials in evidence output.

Workflow

  • Inspect existing changes before editing.
  • Add or update tests for behavior changes.
  • Run the Skill validator after changing .agents/skills/codex-proof.
  • Run python -m unittest discover -s tests -v before completion.
  • Exercise the installed console entry point for CLI changes.

Completion

  • Keep structural, test, runtime, behavior, visual, and artifact claims separate.
  • Report exact commands and observable results.
  • Leave failed or pending claims visible.
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. 2mo ago First seen · 23 lines · 163 tokens per session scan A 3c14e9ef843d

Subscribe to this mod's changes

codex-proof AGENTS.md is an instructions file published in the GitHub repository serein-nyx/codex-proof (11 stars, last pushed 2mo ago), licensed MIT. It adds 163 tokens to every session, about $0.0007 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.

Related

codex-proof AGENTS.md compared with instructions from other repositories

codex-proof AGENTS.md next to 6 instructions from other repositories
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codex-proof AGENTS.mdserein-nyx/codex-proofInstructions file112mo agoMITA163Codex, OpenCode
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deepseek-harness AGENTS.mddeepseek-ai/deepseek-harnessInstructions file274k2d agoMITA4,313Codex, OpenCode