agentic-sandbox: Instructions file for Codex

AGENTS.md

agentic-sandbox AGENTS.md is an instructions file for Codex, OpenCode from jmagly/agentic-sandbox. It costs 2,449 tokens per session, scanned B, original, AGPL-3.0.

Repository instructions that tell coding agents how the jmagly/agentic-sandbox project is organized and worked on.

In plain words
What is it for?
Understanding the codebase, its technology choices, development commands, and file structure.
Why use it?
They give an agent the project context and required commands, reducing guesswork when making changes.

Instructions file for CodexOpenCode

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

This is jmagly/agentic-sandbox's own configuration. It tells Codex and OpenCode how to work on agentic-sandbox 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 agentic-sandbox configures →

Reuse

Borrowing it

Nothing to install: this file belongs to jmagly/agentic-sandbox. 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/jmagly/agentic-sandbox/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/jmagly/agentic-sandbox

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 agentic-sandbox AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/jmagly/agentic-sandbox/agents-md/github.svg)](https://agentmods.dev/instructions/jmagly/agentic-sandbox/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/jmagly/agentic-sandbox/agents-md"><img src="https://agentmods.dev/badge/instructions/jmagly/agentic-sandbox/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 agentic-sandbox AGENTS.md

Your own site · 80×15
<a href="https://agentmods.dev/instructions/jmagly/agentic-sandbox/agents-md"><img src="https://agentmods.dev/badge/instructions/jmagly/agentic-sandbox/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 2,449 This file is loaded in full into every session.
When invoked 2,449 The same file — it is already loaded in full.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 $0.02449 $0.02449
Opus 5.5 $0.00980 $0.00980
Sonnet 5.5 $0.00490 $0.00490
Haiku 4.5 $0.00245 $0.00245

Measured 2mo ago against content hash 9bc88538c268, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

agentic-sandbox AGENTS.md scanned grade B with 1 finding 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.

Reads agent configuration directoriesmediumAgent snooping

.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.

| Codex | `~/.codex/config` | `AGENTS.md` |
AGENTS.md · 258 lines

The source is not reproduced here

Licensed AGPL-3.0

The repository is licensed AGPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

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 · 258 lines · 2,449 tokens per session scan B 9bc88538c268

Subscribe to this mod's changes

agentic-sandbox AGENTS.md is an instructions file published in the GitHub repository jmagly/agentic-sandbox (14 stars, last pushed 2mo ago), licensed AGPL-3.0. It adds 2,449 tokens to every session, about $0.0098 per session on Opus 5.5. A static security scan graded it B with 1 finding (reads agent configuration directories). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

agentic-sandbox AGENTS.md compared with instructions from other repositories

agentic-sandbox AGENTS.md next to 6 instructions from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
agentic-sandbox AGENTS.mdjmagly/agentic-sandboxInstructions file142mo agoAGPL-3.0B2,449Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA9,719GitHub Copilot
next.js AGENTS.mdvercel/next.jsInstructions file143ktodayMITA7,461Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchainInstructions file149kyesterdayMITA4,680Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA5,516GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA3,093GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harnessInstructions file274k2d agoMITA4,313Codex, OpenCode