skills: Instructions file for Codex

AGENTS.md

skills AGENTS.md is an instructions file for Codex, OpenCode from nagaakihoshi/skills. It costs 899 tokens per session, scanned A, original, MIT.

Instructions for creating and maintaining agent skills in the nagaakihoshi/skills repository, where each skill has metadata and an SKILL.md file.

In plain words
What is it for?
Use them when adding or releasing a skill, including creating its files, updating its version, and running Tessl checks.
Why use it?
They clarify the required folder structure, naming, versioning, optimization, and validation steps.

Instructions file for CodexOpenCode

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

This is nagaakihoshi/skills's own configuration. It tells Codex and OpenCode how to work on skills 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 skills configures →

Reuse

Borrowing it

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

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 skills AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/nagaakihoshi/skills/agents-md.svg)](https://agentmods.dev/instructions/nagaakihoshi/skills/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/nagaakihoshi/skills/agents-md"><img src="https://agentmods.dev/badge/instructions/nagaakihoshi/skills/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 899 This file is loaded in full into every session.
When invoked 899 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 $0.00899 $0.00899
Opus 5 $0.00449 $0.00449
Sonnet 5 $0.00180 $0.00180
Haiku 4.5 $0.00090 $0.00090

Measured 6d ago against content hash bba4aa775a6d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

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 6d 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 · 122 lines

How it starts

The opening of the file, as written. The whole thing — 122 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

This file provides guidance to AI agents working with code in this repository.

Project Overview

This repository contains agent skills — custom tools and capabilities for AI agents, managed with Tessl.

Repository Structure

skills/<name>/
├── tile.json   # Skill metadata and version
└── SKILL.md    # Agent instructions

Development Workflow

Creating a skill

Note: tessl skill new has a bug where it generates a nested structure. Create skills manually.

// skills/<name>/tile.json
{
  "name": "nagaakihoshi/<name>",
  "version": "0.1.0",
  "summary": "<description>",
  "private": true,
  "skills": {
    "<name>": {
      "path": "SKILL.md"
    }
  }
}

Naming convention

Use gerund form for skill names (e.g., developing-tessl-skills, not tessl-skill-dev).

Preparing a skill for PR

  1. Optimize: tessl skill review --optimize skills/<name>
    • Aim for a score of 70% or higher
  2. Bump version in tile.json following semver
  3. Lint: tessl skill lint skills/<name>
  4. Stage both SKILL.md and tile.json

Note: tessl skill review requires local login (tessl login). It cannot authenticate in CI.

CI behavior

  • PR: tessl skill lint runs on changed skills only
  • Merge to main: tesslio/publish@main publishes to the Tessl Registry

Skill Authoring Guidelines

Follow the Claude skill best practices.

Frontmatter

  • name: lowercase, hyphens only, max 64 chars, gerund form (e.g., processing-pdfs)
  • description: third person, max 1024 chars, must describe what the skill does AND when to use it
# Good
description: Runs the complete local development lifecycle for a Tessl skill. Use when preparing a skill for pull request or publication.

# Bad — first person, no trigger condition
description: Helps you prepare Tessl skills for publishing.

Read the full file on GitHub · 122 lines

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. 6d ago First seen · 122 lines · 899 tokens per session scan A bba4aa775a6d

Subscribe to this mod's changes

skills AGENTS.md is an instructions file published in the GitHub repository nagaakihoshi/skills (2 stars, last pushed 3mo ago), licensed MIT. It adds 899 tokens to every session, about $0.0045 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 2026-08-31.

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