harness-engineering-marketplace

harness-engineering
Agent-first development toolkit for Claude Code

Install · Skills · Commands · Hooks · Contributing

---

Bootstrap knowledge bases, shape requirements, breadboard systems, and enforce standards — all from inside Claude Code.

Built on the methodology behind ~1M LOC across 1,500 PRs with zero manually-written code.

What's Inside

Component	Count	Summary
Skills	5	harness-engineering, git-worktree, shaping, tdd, playwright-cli
Commands	8	/harness-init, /harness-shape, /shaping, /breadboarding, and more
Hooks	4	Lint-on-save, shaping ripple checks, plan capture, plan pipeline
MCP Servers	1	context7 — framework documentation lookup

Install

From the marketplace (recommended)

Inside Claude Code:

/plugin marketplace add lattice-technologies-inc/harness-engineering
/plugin install harness-engineering@harness-engineering-marketplace

From a local clone

git clone https://github.com/lattice-technologies-inc/harness-engineering.git
cd harness-engineering

# Load for a single session
claude --plugin-dir .

From a local path (persistent)

/plugin marketplace add /path/to/harness-engineering
/plugin install harness-engineering@harness-engineering-marketplace

Scope options: Add --scope project to share with your team (writes to .claude/settings.json) or --scope local for this repo only (gitignored).

Quick Start

/harness-init          # Bootstrap knowledge base in your repo
/harness-shape         # Fill placeholders with real project context
/shaping               # Shape a feature (requirements + solution options)
/breadboarding         # Map system into affordance tables

New repo:

/harness-init  -->  /harness-shape  -->  /harness-eslint (optional)

Existing repo:

/harness-init  -->  /harness-onboard  -->  /harness-shape  -->  /harness-eslint (optional)

Skills

harness-engineering

Bootstrap an agent-first knowledge base in any repository. Creates AGENTS.md, structured docs, golden principles, quality scoring, and mechanical enforcement.

What gets scaffolded:

• AGENTS.md — table of contents (not an encyclopedia)
• ARCHITECTURE.md — domain map
• docs/ — golden principles, quality scores, tech debt tracker, design docs, plans pipeline
• .claude/ — commands, hooks, settings
• scripts/harness/knowledge-check.sh — CI-ready structural checks

shaping

Shape Up methodology adapted for LLMs. Three commands covering the full pre-code workflow:

Command	Phase	Output
/shaping	Define problem + solution options	Requirements (R), Shapes (S), fit checks
/breadboarding	Map into concrete affordances	Places, UI/Code affordances, wiring, vertical slices
/breadboard-reflection	Validate design	Smell detection, naming tests, wiring coherence

tdd

Test-driven development with vertical red-green-refactor loops. Enforces behavior-over-implementation testing, boundary-only mocking, and incremental tracer bullet workflow.

git-worktree

Manage Git worktrees for isolated parallel development. Handles env file copying, .worktree-config for multi-agent coordination, and cleanup.

playwright-cli

Playwright-powered browser automation CLI. Full browser control with snapshots, tabs, cookies, network mocking, tracing, and CDP support (connect to Arc, Chrome, Edge).

Commands

Command	Description
/harness-init	Bootstrap knowledge base scaffolding
/harness-shape	Fill placeholders with real project context
/harness-standards	Alias for /harness-shape
/harness-onboard	Audit existing repo and generate gap-fill plan
/harness-eslint	Add agent-readable ESLint enforcement (JS/TS)
/shaping	Iterate on requirements and solution shapes with fit checks
/breadboarding	Map systems into affordance tables with wiring
/breadboard-reflection	Validate breadboard design for smells

Hooks

Hook	Trigger	What it does
lint-on-save	PostToolUse on Edit/Write	Runs ESLint, ruff, or shellcheck and feeds errors back to the agent
shaping-ripple	PostToolUse on Edit/Write	Checks if shaping doc edits need to ripple to related docs
plan-capture	PostToolUse on ExitPlanMode	Reminds agent to file the approved plan in docs/plans/
plan-pipeline	Stop	Verifies plans are in the correct pipeline stage before session ends

ESLint Rules