feat(PROJ-000): package harness as Claude Code plugin

.claude-plugin/marketplace.json

@@ -0,0 +1,15 @@
+{
+  "name": "devartist",
+  "owner": {
+    "name": "Henry Cordes",
+    "email": "development@devartist.nl",
+    "url": "https://devartist.nl"
+  },
+  "plugins": [
+    {
+      "name": "ai-engineering-workflow",
+      "source": "./",
+      "description": "Spec-driven AI-assisted engineering harness: task skills with a self-hardening Lessons loop, reviewer and test-writer subagents, and a new-spec scaffolding command."
+    }
+  ]
+}

.claude-plugin/plugin.json

@@ -0,0 +1,23 @@
+{
+  "name": "ai-engineering-workflow",
+  "version": "1.0.0",
+  "description": "Spec-driven AI-assisted engineering harness: commit, PR-description, safe-rollout and scaffolding skills, reviewer and test-writer subagents, a new-spec command, and the improve-skill hardening loop that turns session failures into permanent fixes.",
+  "author": {
+    "name": "Henry Cordes",
+    "email": "development@devartist.nl",
+    "url": "https://devartist.nl"
+  },
+  "homepage": "https://github.com/HenryCordes/ai-engineering-workflow",
+  "repository": "https://github.com/HenryCordes/ai-engineering-workflow",
+  "license": "MIT",
+  "keywords": [
+    "claude-code",
+    "workflow",
+    "context-engineering",
+    "skills",
+    "spec-driven-development"
+  ],
+  "skills": "./.claude/skills/",
+  "commands": ["./.claude/commands/"],
+  "agents": ["./.claude/agents/"]
+}

README.md

@@ -67,6 +67,24 @@ every rule exists (see the Lessons in
 [`scaffold-module`](.claude/skills/scaffold-module/SKILL.md), grown out of the bugs in the
 [case study](docs/CASE_STUDY.md)).
 
+### Use this setup in your own repo
+
+The whole harness is also a **Claude Code plugin** — the manifest in
+[`.claude-plugin/`](.claude-plugin) points at the same `.claude/` folders this repo uses
+itself, so there's exactly one copy of everything. Install:
+
+```
+/plugin marketplace add HenryCordes/ai-engineering-workflow
+/plugin install ai-engineering-workflow@devartist
+```
+
+You get the skills (`commit`, `pr-description`, `safe-rollout`, `scaffold-module`,
+`improve-skill` — Lessons changelogs included), the subagents (`write-test`,
+`review-standards`) and the `new-spec` command. Repo-local wiring (the SessionStart hook,
+`settings.json` permissions, git hooks) deliberately stays out of the plugin — that's your
+project's business. Note `scaffold-module` assumes this repo's module layout; the rest is
+project-agnostic.
+
 **And CI holds both rules to account.** Stated rules drift unless something enforces them,
 so the same pipeline that runs lint and tests also runs
 [`check-context-budget`](scripts/check-context-budget.mjs) — the build fails when
@@ -137,6 +155,7 @@ measured by what users feel, backed by tests, not by how clever the code looks.
 | [`.claude/`](.claude) | Permissions + session-start hook |
 | [`.husky/`](.husky) | Real git hooks matching `docs/GIT_HOOKS.md` — not just documentation |
 | [`scripts/`](scripts) | CI guardrails for the context itself — budget + link checks |
+| [`.claude-plugin/`](.claude-plugin) | Plugin + marketplace manifests — install this harness into your own repo |
 | [`.github/`](.github) | CI workflow + PR template the skills/docs reference |
 | [`.editorconfig`](.editorconfig) | Editor-level formatting baseline matching `docs/DEVELOPMENT.md` |
 | [`.claude/workflows/parallel-review.js`](.claude/workflows/parallel-review.js) | A runnable multi-agent workflow: parallel reviewers + adversarial verification |