Cross Harness Skills

Cross-Harness Skills

Marketplace-style repository for portable agent skills that can be shared across Codex, Claude Code, and compatible local harnesses.

The repository is organized as a marketplace catalog with one initial plugin:

.
├── .agents/plugins/marketplace.json
├── .claude-plugin/marketplace.json
└── plugins/
    └── cross-harness-skills/
        ├── .codex-plugin/plugin.json
        ├── .claude-plugin/plugin.json
        └── skills/

Install

Claude Code

claude plugin marketplace add eric-tramel/cross-harness-skills
claude plugin install cross-harness-skills@eric-cross-harness-skills

For local testing from this checkout:

claude plugin marketplace add .
claude plugin install cross-harness-skills@eric-cross-harness-skills

Codex

This repo includes a Codex marketplace manifest at .agents/plugins/marketplace.json and a plugin manifest at plugins/cross-harness-skills/.codex-plugin/plugin.json.

For local testing from this checkout:

codex plugin marketplace add .

For remote install:

codex plugin marketplace add eric-tramel/cross-harness-skills

After adding the marketplace, install or enable cross-harness-skills from the Codex plugin UI.

Add A Skill

Create a new skill directory under plugins/cross-harness-skills/skills/:

plugins/cross-harness-skills/skills/<skill-name>/SKILL.md

Use lowercase kebab-case for <skill-name>. Keep the core workflow portable, and put harness-specific details in clearly labeled sections or companion reference files.

Validate

Codex plugin validation:

python3 /Users/eric/.codex/skills/.system/plugin-creator/scripts/validate_plugin.py plugins/cross-harness-skills

Claude Code validation, when the CLI is available:

claude plugin validate .
claude plugin validate plugins/cross-harness-skills

Release Notes

When publishing a release, update the version field in both plugin manifests:

• plugins/cross-harness-skills/.codex-plugin/plugin.json
• plugins/cross-harness-skills/.claude-plugin/plugin.json