Harness

Harness Marketplace

Claude Code plugin marketplace for The Harness. Ships skills and agents that power skillflows and missions.

Current version: 0.2.0

Installation

# Install the harness plugin globally
claude plugin add /path/to/marketplace/harness

# Or from the marketplace registry
claude plugin add makers-and-breakers/harness

Skills

Skills are invocable steps in a skillflow. Each skill defines what Claude does during that step.

Operator-facing skills

These are available in the skillflow picker:

Skill	Command	Description
Shape	/harness:shape	Explore a fuzzy idea against the codebase. Conversational feasibility assessment.
Brief	/harness:brief	Write a structured one-pager — goals, scope, risks, non-goals. Fire-and-forget.
Ground	/harness:ground	Turn a brief into a buildable spec rooted in the codebase — APIs, data shapes, edge cases.
Design	/harness:design	Visual mockup (HTML/Tailwind) of a UI surface. Produces variant artifacts.
Prototype	/harness:prototype	Standalone HTML demo proving a concept before integration.
Iterate	/harness:iterate	Plan + Build + Review on the connected repo. Creates a feature branch with commits.
Report	/harness:report	Structured status or summary document.
Push	/harness:push	Push the current feature branch and optionally open a PR.

Internal phase skills

These are spawned by the iterate orchestrator and are not directly invocable:

Skill	Phase of
iterate-plan	Iterate — planning phase
iterate-work	Iterate — build phase
iterate-review	Iterate — review phase
iterate-summary	Iterate — summary artifact
compound-skillflow	Post-completion learning extraction

Utility skills

Skill	Command	Description
Init	/harness:init	Initialize a new project with harness configuration.
Skillflow	/harness:skillflow	Start a new skillflow from the CLI.
Mission	/harness:mission	Start a new mission from the CLI.
Identity (Operator)	/harness:identity-operator	Define the operator identity for the project.
Identity (Company)	/harness:identity-company	Define the company identity.
Identity (Brand)	/harness:identity-brand	Define the brand identity.

Agents

Agents are autonomous workers dispatched by the orchestrator.

Agent	Model	Description
Mission Lead	Opus	Orchestrates mission execution — reads the task DAG, coordinates workers, manages lifecycle.
Mission Worker	—	Executes a single mission task in an isolated worktree.
Skillflow Runner	—	Runs interactive skillflow steps with all harness skills preloaded.
App Builder	—	Builds internal tools for the Builder module (Next.js + Tailwind + TypeScript).
App Reviewer	—	Reviews generated app code for security, correctness, and quality. Read-only.
Harness Reviewer	—	Reviews completed task output against requirements and project conventions.

Structure

marketplace/
  .claude-plugin/
    marketplace.json      Marketplace registry manifest
  harness/
    .claude-plugin/
      plugin.json          Plugin manifest (name, version, description)
    .mcp.json              MCP server configuration
    skills/                Skill definitions (SKILL.md per skill)
    agents/                Agent definitions (one .md per agent)
    templates/             Identity templates (operator, company, brand)
    docs/                  Plugin documentation (operator-view-spec, etc.)

Creating a new skill

1. Create a directory under marketplace/harness/skills/<name>/
2. Add a SKILL.md with frontmatter:

---
name: my-skill
description: Use when the user says "/harness:my-skill" or wants to ...
---

Instructions for Claude when this skill runs.

1. Bump the version in harness/.claude-plugin/plugin.json and marketplace.json

Creating a new agent

1. Add a .md file under marketplace/harness/agents/
2. Include frontmatter with name, description, and optionally model and color
3. The agent body contains the system prompt

Publishing

After making changes:

1. Bump version in both marketplace/.claude-plugin/marketplace.json and marketplace/harness/.claude-plugin/plugin.json
2. Commit and push
3. Users update via claude plugin update harness