agent-skills AGENTS.md

Development notes for creating agent skills and their frontmatter, which is the metadata block at the top of a skill file. It explains a naming rule needed for correct namespaced display.

In plain words
What is it for?
Use it when creating or reviewing skill metadata, especially when the skill should appear with its repository namespace.
Why use it?
It prevents a frontmatter setting from replacing the intended skill name with an incorrect or generic label.

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/codagent-ai/agent-skills/agents-md
Clone the repo
git clone --depth 1 https://github.com/Codagent-AI/agent-skills

Made for: Codex, OpenCode.

Per session 65 This file is loaded in full into every session.
When invoked 65 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 $0.00065 $0.00065
Opus 5 $0.00032 $0.00032
Sonnet 5 $0.00013 $0.00013
Haiku 4.5 $0.00006 $0.00006

Measured 2d ago against content hash 9b76e1846233, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

agent-skills 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 2d 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

Copies of this mod

1 near-identical copy found in the catalogue:

AGENTS.md · 6 lines

What it actually says

Agent Skills — Development Notes

Skill frontmatter

Do NOT add a name field to skill frontmatter. The name field overrides the skill's display prefix, causing it to show an incorrect or generic name instead of the proper namespaced prefix (e.g. codagent:handoff).

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. 2d ago First seen · 6 lines · 65 tokens per session scan A 9b76e1846233

Subscribe to this mod's changes

agent-skills AGENTS.md is an instructions file published in the GitHub repository Codagent-AI/agent-skills (30 stars, last pushed 1mo ago), licensed MIT. It adds 65 tokens to every session, about $0.0003 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.