marketplace AGENTS.md

marketplace AGENTS.md is an instructions file for Codex, OpenCode from taivop/marketplace. It costs 681 tokens per session, scanned A, original, MIT.

A guide for maintaining a marketplace that distributes reusable agent add-ons through Anthropic Claude Code and Codex. It describes the folder layout, the authoritative files, generated metadata, and validation scripts.

In plain words
What is it for?
Adding or updating plugin packages, generating manifests and marketplace data, and validating Claude Code plugins and Codex skills.
Why use it?
It clarifies which files are the source of truth and how to keep both marketplace distributions consistent.

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/taivop/marketplace/agents-md
Clone the repo
git clone --depth 1 https://github.com/taivop/marketplace

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 marketplace AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/taivop/marketplace/agents-md.svg)](https://agentmods.dev/instructions/taivop/marketplace/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/taivop/marketplace/agents-md"><img src="https://agentmods.dev/badge/instructions/taivop/marketplace/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 681 This file is loaded in full into every session.
When invoked 681 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 $0.00681 $0.00681
Opus 5 $0.00341 $0.00341
Sonnet 5 $0.00136 $0.00136
Haiku 4.5 $0.00068 $0.00068

Measured 5d ago against content hash dbe889bf74b7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

marketplace 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 5d 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 · 91 lines

How it starts

The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Marketplace Agent Guide

This repository is a dual-distribution marketplace for reusable agent plugins:

  1. Anthropic Claude Code marketplace plugins.
  2. Codex installable skills.

It is not limited to public-data skills. Any useful, reusable agent plugin can live here (for example, future additions such as skill-self-coaching).

Core Layout

.
├── .claude-plugin/marketplace.json
├── skills/
│   └── <plugin-package>/
│       ├── SKILL.md
│       ├── .claude-plugin/plugin.json
│       └── ...
├── scripts/
│   ├── generate_plugin_manifests.py
│   ├── generate_marketplace.py
│   ├── validate_codex_skills.py
│   └── validate_anthropic_plugins.py
└── .github/workflows/validate-distribution.yml

Source Of Truth

For each package, SKILL.md frontmatter is authoritative.

Expected frontmatter fields:

  1. Required:
    • name
    • description
  2. Distribution metadata (recommended and used by generators):
    • metadata.distribution.publish_anthropic: true/false
    • metadata.distribution.plugin_name: Anthropic plugin name
    • metadata.distribution.plugin_version: SemVer (X.Y.Z)
    • metadata.distribution.plugin_author: display author name

Generated files:

  1. <package>/.claude-plugin/plugin.json
  2. /.claude-plugin/marketplace.json

Do not hand-edit generated files. Run generators instead.

Add A New Plugin Package

  1. Create the package directory at skills/<slug>.
  2. Add SKILL.md with valid frontmatter.
  3. Add any package-specific resources (agents/, scripts/, references/, assets/, docs).
  4. Set metadata.distribution.* values in SKILL.md.
  5. Run generation + validation:
    • python3 scripts/generate_plugin_manifests.py
    • python3 scripts/generate_marketplace.py
    • python3 scripts/validate_codex_skills.py
    • python3 scripts/validate_anthropic_plugins.py
  6. Ensure clean generation check:
    • python3 scripts/generate_plugin_manifests.py --check
    • python3 scripts/generate_marketplace.py --check

Read the full file on GitHub · 91 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. 5d ago First seen · 91 lines · 681 tokens per session scan A dbe889bf74b7

Subscribe to this mod's changes

marketplace AGENTS.md is an instructions file published in the GitHub repository taivop/marketplace (17 stars, last pushed 4d ago), licensed MIT. It adds 681 tokens to every session, about $0.0034 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.

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