jeangnc

Harness Kit — Development skill for Claude Code

Development community

Framework for building multi-agent harnesses — author plugins once, target every vendor (Claude Code, Codex, …).

How to install Harness Kit

This entry records only its repository, not the path inside it, so there is no exact command to give. Open jeangnc/harness-kit and copy the folder into ~/.claude/skills/, or the file into ~/.claude/agents/.

What Harness Kit does

Framework for building multi-agent harnesses — author plugins once, target every vendor (Claude Code, Codex, …).

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README

Harness Kit

`harness-kit` is a framework for building multi-agent harnesses — author plugins once, target every vendor.

Quickstart

pnpm add @jean.gnc/harness-kit
harness init --marketplace my-harness --vendors claude,codex
# author src/plugins//... (see docs/authoring.md)
harness compile
harness install

`harness` is the canonical bin; `harness-kit` is an alias.

How it works

You write plugins and configs once under `src/`, declare which vendors to target, and `harness compile` emits a per-vendor `dist/` tree that `harness install` links into each vendor's home.

`harness.yaml`

A declarative repo config with two required fields and one optional one:

marketplace: my-harness
vendors:
  - claude
  - codex
roots:                       # optional — named include aliases (see docs/authoring.md)
  shared: src/shared

Created by `harness init`. Read automatically by `compile`, `install`, and `uninstall` via `--repo` (default `.`).

Vendors

A vendor is a named target with a home directory, a per-vendor manifest path, an `emitPluginManifest` hook, `install`/`uninstall` hooks, and an optional `aliases` hook for fan-out symlink destinations. Built-in:

claude — registers plugins via claude plugin install; creates a CLAUDE.md symlink whenever an AGENTS.md config file is linked.
codex — primes the local cache by copying compiled plugins, then runs codex plugin marketplace add; merges config.toml into ~/.codex/config.toml instead of linking it, so the app's own state never lands in the repo.

Writing your own vendor: see [docs/vendors.md](./docs/vendors.md).

Source layout

You author a single source manifest, `src/.claude-plugin/marketplace.json`, listing which plugins to compile. `compile` reads it and emits a per-vendor manifest at `dist//.claude-plugin/marketplace.json` — that emitted one is the marketplace each vendor's CLI actually installs.

Under `src/`:

| Path | What it is | | --- |