Web Builder Harness — Development skill for Claude Code

Web Builder Harness

[中文](README.zh-CN.md) · English

A Claude Code plugin that turns a one-sentence idea into a small, verified web app. It plans the product, builds it in sprints, and checks every sprint with independent agents, enforced by hooks so the builder cannot grade its own work.

What it does

1. Plan. A planner asks a few focused questions, writes a product spec with a design direction, and produces a feature list. Each feature has concrete user scenarios, including at least one tagged [错误] / [error] or [边界] / [edge] case.
2. Confirm once. You approve the feature list. From then on the scope is frozen and recorded with a hash.
3. Build in sprints. Each sprint goes through generate → evaluate → product acceptance. A sprint passes only when both graders pass it. A sprint gets up to 3 cycles; after that the orchestrator asks you what to do.

The roles never overlap:

Role	Writes	Does not
Planner	CLAUDE.md, .web-builder/spec.md, feature_list.json (once)	write product code
Generator	product code, tests/	touch .web-builder/, change pass status
Evaluator	.web-builder/evidence/, its verdict	edit code, score visual taste
Product acceptance (PA)	its verdict only	run the app, edit any file

Install

Requires Python 3 on your `PATH` (`python3`). The scripts use only the standard library.

In Claude Code:

/plugin marketplace add coldingcode/web-builder-harness
/plugin install web-builder@web-builder-harness

Then, in an empty folder (or an existing repo), start a run:

/web-builder a pomodoro timer web app with a task list

Check progress at any time with `/web-builder status`, and resume an interrupted run with `/web-builder resume`.

Gates

Hooks in `web-builder/hooks/hooks.json` run `web-builder/scripts/hooks.py`. Blocking uses exit code 2, as the Claude Code hook protocol requires.

• State is script-owned. state.json, plan_confirmed.json and