agent-box AGENTS.md

A set of project instructions for agent-box, including development commands, Rust wrapper conventions, image-build notes, and architecture decision records. Nix is a tool for reproducible development environments and builds.

In plain words
What is it for?
Use it when developing agent-box, especially before committing code, working on Rust wrappers, building the image component, or updating architecture documentation.
Why use it?
It records the project's required checks and conventions so changes are built, formatted, and reviewed consistently. It also explains where related documentation and build inputs come from.

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/0xferrous/agent-box/agents-md
Clone the repo
git clone --depth 1 https://github.com/0xferrous/agent-box

Made for: Codex, OpenCode.

Per session 373 This file is loaded in full into every session.
When invoked 373 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 $0.00373 $0.00373
Opus 5 $0.00187 $0.00187
Sonnet 5 $0.00075 $0.00075
Haiku 4.5 $0.00037 $0.00037

Measured 3d ago against content hash d65f282c3c18, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

agent-box 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 3d 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 · 45 lines

What it actually says

  • use nix develop --command to run the commands in the flake's devshell
  • use conventionalcommits.org pattern when writing commit messages

pre commit

  • format code with cargo fmt
  • check code with cargo check
  • check clippy with cargo clippy
  • always keep the docs and README files in sync with the code changes (root and crate-level READMEs)
  • keep the table of contents in the root README.md up to date whenever a change is made

image

The image flake uses a custom docker.nix from the nix input (github:0xferrous/nix/extra-args).

To get the nix store path of the nix flake input:

nix eval --raw --impure --expr '(builtins.getFlake (toString ./image)).inputs.nix'
# Returns: /nix/store/<hash>-source

To read the docker.nix file from that input:

cat $(nix eval --raw --impure --expr '(builtins.getFlake (toString ./image)).inputs.nix')/docker.nix

This is referenced in image/flake.nix as:

pkgs.callPackage "${nix}/docker.nix" { ... }

wrappers

  • implement wrapper binaries in Rust (keep wrapper runtime language consistent across wrappers/)

portal ADR

  • Portal architecture decisions are tracked in adr/.
  • Current accepted ADRs:
    • adr/0001-agent-portal.md
    • adr/0002-transparent-portal-wrappers.md
  • For portal work, keep implementation and configuration aligned with these ADRs.
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. 3d ago First seen · 45 lines · 373 tokens per session scan A d65f282c3c18

Subscribe to this mod's changes

agent-box AGENTS.md is an instructions file published in the GitHub repository 0xferrous/agent-box (35 stars, last pushed 3mo ago), licensed MIT. It adds 373 tokens to every session, about $0.0019 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 2026-08-30.