Borrowing it
Nothing to install: this file belongs to EEstevanell/codex-planning-kit. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/EEstevanell/codex-planning-kit/main/AGENTS.mdgit clone --depth 1 https://github.com/EEstevanell/codex-planning-kitWrote 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.
[](https://agentmods.dev/instructions/eestevanell/codex-planning-kit/agents-md)<a href="https://agentmods.dev/instructions/eestevanell/codex-planning-kit/agents-md"><img src="https://agentmods.dev/badge/instructions/eestevanell/codex-planning-kit/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.
<a href="https://agentmods.dev/instructions/eestevanell/codex-planning-kit/agents-md"><img src="https://agentmods.dev/badge/instructions/eestevanell/codex-planning-kit/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.01208 | $0.01208 |
| Opus 5.5 | $0.00483 | $0.00483 |
| Sonnet 5.5 | $0.00242 | $0.00242 |
| Haiku 4.5 | $0.00121 | $0.00121 |
Grade A, and why
codex-planning-kit 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.
How it starts
The opening of the file, as written. The whole thing — 68 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Guidance for Codex Agents
This repository is a template for a Codex workflow based on issue cards and ExecPlans. Before using it in a real project, replace all TEMPLATE placeholders with repo-specific details.
Core expectations
- Align proposed solutions with the existing architecture and coding conventions observed in the codebase.
- Prioritize best practices, code clarity, and long-term maintainability with every change.
- Optimize for small blast radius and minimal behavioral change (risk), not small line-count. Avoid unrelated "drive-by" edits outside the code path you are already touching.
- Avoid overengineering and speculative abstractions; pick the simplest design that meets the requirement without adding clutter.
- Never delete directories or files unless the user explicitly asks for that deletion in the same turn. Never delete unrelated files. If cleanup is needed, list candidates and ask first.
- Use TDD (red-green-refactor) for behavioral changes: start with a focused failing test, implement until green, then refactor. If automated tests are impractical, document why and provide a concrete manual verification path.
- Local refactors (within the touched file/module, no public API changes) are encouraged; keep them scoped, mechanical, and reviewable.
- Significant refactors (file moves, new-file extractions, cross-cutting redesigns, or public API changes) require explicit approval in the issue card or ExecPlan before implementation; list affected files and intended invariants.
- Ground every decision in prior art. Prefer repo sources (issue cards, ExecPlans, docs, README); external sources are citations only. Restate the relevant rule/constraint in the card or plan so implementation stays self-contained.
- When multiple valid approaches exist, prefer the one with the best maintainability-to-risk ratio; do not avoid a good refactor solely to minimize diff size.
- Do not implement fallback behavior that masks invalid states; fail explicitly with clear errors and block unsafe flows.
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 · 68 lines · 1,208 tokens per session scan A 4c4abd09b570
codex-planning-kit AGENTS.md is an instructions file published in the GitHub repository EEstevanell/codex-planning-kit (2 stars, last pushed 8mo ago), licensed Apache-2.0. It adds 1,208 tokens to every session, about $0.0048 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.
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