feat: ship the skill set as a native Claude Code plugin

Add a Claude Code plugin marketplace so the promoted skills can be
installed as a managed, read-only bundle (subscribe rather than fork),
alongside the existing skills.sh installer.

- Enrich .claude-plugin/plugin.json with marketplace metadata (version,
  description, author, license, keywords); keep the curated promoted-only
  skills array.
- Add .claude-plugin/marketplace.json making the repo its own
  single-plugin marketplace (mattpocock-skills@mattpocock).
- README: document /plugin install alongside skills.sh, and the
  subscribe-vs-fork tradeoff.
- CLAUDE.md: extend the promoted-set invariant to cover marketplace.json
  and plugin.json/package.json version sync.
- ADR 0002: record why Claude ships now and a native Codex plugin is
  deferred (Codex skills field is single-path + drops symlinks, which
  can't express a curated subset of a bucketed repo without a restructure).

Verified: 'claude plugin validate . --strict' passes, and marketplace
add -> install resolves all 21 promoted skills at v1.2.0.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.agents/adr/0002-ship-as-a-claude-code-plugin.md

@@ -0,0 +1,28 @@
+# Ship the skill set as a native Claude Code plugin; defer a native Codex plugin
+
+These skills have always been installable via [skills.sh](https://skills.sh/mattpocock/skills) (`npx skills add mattpocock/skills`), which copies editable skill files into a user's project across Claude Code, Codex, and other Agent-Skills-standard harnesses. A recurring request is a **plug-and-play** distribution: subscribe to the set as a read-only, always-current bundle you don't edit, rather than a fork you own. That is exactly what native plugin systems provide.
+
+We ship a native **Claude Code plugin** and, for now, **defer** a native **Codex plugin**. The split is forced by how each ecosystem's plugin manifest selects skills, against this repo's bucketed layout.
+
+## The constraint: bucketed skills vs. single-path selection
+
+Skills live in bucket folders under `skills/` — `engineering/` and `productivity/` are **promoted** (shipped); `misc/`, `personal/`, `in-progress/`, and `deprecated/` are **not**. A plugin must expose only the promoted set, which spans two of those bucket folders.
+
+- **Claude Code** — `.claude-plugin/plugin.json` accepts `skills` as an **array of explicit skill-directory paths**. We list the promoted skills one by one, exclude everything else with zero ambiguity, and add `.claude-plugin/marketplace.json` so the repo is its own single-plugin marketplace. Verified end to end: `claude plugin validate . --strict` passes, and `marketplace add` → `install` resolves all promoted skills.
+
+- **Codex** — `.codex-plugin/plugin.json` accepts `skills` only as a **single path string** (arrays are rejected with `missing or invalid plugin.json`), and Codex discovers `SKILL.md` files recursively under it. There is no way to name two bucket folders, or to curate a subset, from one path. Two escape hatches were tested and rejected:
+  - Pointing at `./skills/` would also ship `deprecated/`, `in-progress/`, `personal/`, and `misc/` — retired, draft, and personal skills we deliberately don't promote.
+  - A curated flat directory of **symlinks** into the buckets does not survive install: Codex copies the plugin tree into its cache and **drops symlinks**, so the skills arrive empty.
+
+The only robust ways to give Codex a single promoted-only path are (a) **restructure** so `skills/` contains only promoted skills (moving the non-promoted buckets out — a large blast radius across `CLAUDE.md`, `scripts/link-skills.sh`, the bucket READMEs, and the local dev workflow that relies on `in-progress/` and `personal/`), or (b) **commit duplicate copies** of promoted skills into a flat directory (a sync burden and a second source of truth). Both are structural decisions, not something to bundle into shipping the Claude plugin. This is very likely the original, half-remembered reason a plugin wasn't shipped earlier: the manifest formats didn't cleanly express a curated subset of a bucketed repo.
+
+## Decision
+
+- Ship the **Claude Code plugin** now (`.claude-plugin/plugin.json` + `.claude-plugin/marketplace.json`), curated to the promoted set, as the headline v1.2 deliverable.
+- Keep **skills.sh** as the universal installer — it already serves Codex and other harnesses today, so no Codex user is left without an install path.
+- **Defer** the native Codex plugin until we decide between restructuring `skills/` to promoted-only vs. committing a generated flat copy. Revisit when Codex either supports a `skills` array / include-list or preserves symlinks on install.
+
+## Invariants this creates
+
+- Every promoted skill has an entry in `.claude-plugin/plugin.json`'s `skills` array (this already stood as a `CLAUDE.md` rule; it now also gates the plugin's contents).
+- `.claude-plugin/plugin.json`'s `version` tracks `package.json`'s version — bump both together on release. Claude uses the plugin `version` to decide when installed users see an update.

.changeset/ask-matt-wayfinder-guidance.md

@@ -1,10 +0,0 @@
----
-"mattpocock-skills": patch
----
-
-Make `/ask-matt` clued-up about `/wayfinder` — the heaviest, most cognitively demanding flow.
-
-The router now sharpens the two routing mistakes people most often make with wayfinder:
-
-- **Over-reaching for it.** It's slower and denser than a single grill, so it's flagged as the heaviest flow and reserved for the idea that genuinely won't fit one session — a well-scoped feature belongs on `/grill-with-docs`, not here.
-- **Losing the way at the handoff.** When the map clears, wayfinder hands off, it doesn't build: merge onto the main flow at `/to-spec` (which collapses the map's linked decisions into a buildable plan) rather than looping the map straight into `/implement`. Straight-to-`/implement` is only for efforts that turned out genuinely small.

.changeset/ship-as-claude-plugin.md

@@ -0,0 +1,12 @@
+---
+"mattpocock-skills": minor
+---
+
+Ship the skill set as a native **Claude Code plugin**. The repo is now its own single-plugin marketplace, so you can subscribe to the promoted skills as a managed, read-only bundle instead of copying editable files:
+
+```
+/plugin marketplace add mattpocock/skills
+/plugin install mattpocock-skills@mattpocock
+```
+
+`.claude-plugin/plugin.json` gains full marketplace metadata (version, description, author, license, keywords) and a sibling `.claude-plugin/marketplace.json` lists the plugin. `skills.sh` remains the universal installer (and the path for Codex and other harnesses today); a native Codex plugin is deferred — see `.agents/adr/0002-ship-as-a-claude-code-plugin.md` for why.

.claude-plugin/marketplace.json

@@ -0,0 +1,23 @@
+{
+  "name": "mattpocock",
+  "owner": {
+    "name": "Matt Pocock",
+    "url": "https://www.aihero.dev"
+  },
+  "description": "Matt Pocock's skills for real engineering, as an installable Claude Code plugin.",
+  "plugins": [
+    {
+      "name": "mattpocock-skills",
+      "source": "./",
+      "description": "Matt Pocock's agent skills for real engineering — grilling, spec/ticket flows, TDD, code review, domain modelling and more.",
+      "category": "engineering",
+      "keywords": [
+        "engineering",
+        "skills",
+        "tdd",
+        "code-review",
+        "grilling"
+      ]
+    }
+  ]
+}

.claude-plugin/plugin.json

@@ -1,5 +1,23 @@
 {
   "name": "mattpocock-skills",
+  "version": "1.2.0",
+  "description": "Matt Pocock's agent skills for real engineering — grilling, spec/ticket flows, TDD, code review, domain modelling and more. Plug-and-play, not vibe coding.",
+  "author": {
+    "name": "Matt Pocock",
+    "url": "https://www.aihero.dev"
+  },
+  "homepage": "https://www.aihero.dev/s/skills-newsletter",
+  "repository": "https://github.com/mattpocock/skills",
+  "license": "MIT",
+  "keywords": [
+    "engineering",
+    "skills",
+    "tdd",
+    "code-review",
+    "grilling",
+    "domain-modeling",
+    "productivity"
+  ],
   "skills": [
     "./skills/engineering/ask-matt",
     "./skills/engineering/diagnosing-bugs",

CLAUDE.md

@@ -7,7 +7,9 @@ Skills are organized into bucket folders under `skills/`:
 - `in-progress/` — drafts not yet ready to ship
 - `deprecated/` — no longer used
 
-Every skill in `engineering/` or `productivity/` (the **promoted** buckets) must have a reference in the top-level `README.md` and an entry in `.claude-plugin/plugin.json`. Skills in `misc/`, `personal/`, `in-progress/`, and `deprecated/` must not appear in either.
+Every skill in `engineering/` or `productivity/` (the **promoted** buckets) must have a reference in the top-level `README.md` and an entry in `.claude-plugin/plugin.json`'s `skills` array (the Claude Code plugin ships exactly the promoted set). Skills in `misc/`, `personal/`, `in-progress/`, and `deprecated/` must not appear in either.
+
+The repo is also its own single-plugin Claude Code marketplace: `.claude-plugin/marketplace.json` lists the one `mattpocock-skills` plugin. When bumping the release version, keep `.claude-plugin/plugin.json`'s `version` in sync with `package.json`'s — Claude uses the plugin `version` to decide when installed users see an update. Run `claude plugin validate . --strict` after touching either manifest. Why a Claude plugin but not (yet) a Codex one lives in [.agents/adr/0002-ship-as-a-claude-code-plugin.md](./.agents/adr/0002-ship-as-a-claude-code-plugin.md).
 
 Each skill entry in the top-level `README.md` must link the skill name to its `SKILL.md`.
 

README.md

@@ -39,6 +39,33 @@ npx skills@latest add mattpocock/skills
 
 4. Bam - you're ready to go.
 
+## Install as a Claude Code plugin
+
+Prefer a plug-and-play install you don't maintain by hand? These skills also ship as a native [Claude Code plugin](https://code.claude.com/docs/en/plugins). Instead of copying editable files into your repo, the plugin installs the whole skill set as a managed bundle that updates when I ship a new version — you subscribe rather than fork.
+
+Inside Claude Code:
+
+```
+/plugin marketplace add mattpocock/skills
+/plugin install mattpocock-skills@mattpocock
+```
+
+Or from your shell:
+
+```bash
+claude plugin marketplace add mattpocock/skills
+claude plugin install mattpocock-skills@mattpocock
+```
+
+Then run `/setup-matt-pocock-skills` once per repo, exactly as in the quickstart above.
+
+Two ways to install, two philosophies:
+
+- **[skills.sh](https://skills.sh/mattpocock/skills)** copies the skills into your project so you can hack on them and make them your own.
+- **The plugin** keeps them as a read-only, always-current bundle you don't edit — best when you just want my set to work and follow along as it evolves.
+
+> Using Codex or another agent? The [skills.sh installer](https://skills.sh/mattpocock/skills) already installs these skills into Codex and other Agent-Skills-standard harnesses today. A native Codex plugin is on the roadmap — see [`.agents/adr/0002-ship-as-a-claude-code-plugin.md`](./.agents/adr/0002-ship-as-a-claude-code-plugin.md).
+
 ## Why These Skills Exist
 
 I built these skills as a way to fix common failure modes I see with Claude Code, Codex, and other coding agents.

skills/engineering/ask-matt/SKILL.md

@@ -41,9 +41,7 @@ A starting situation that generates work, then merges onto the main flow.
 
 - **Something's broken** → **`/diagnosing-bugs`**. For the hard ones: the bug that resists a first glance, the intermittent flake, the regression that crept in between two known-good states. It refuses to theorise until it has a **tight feedback loop** — one command that already goes red on *this* bug — then fixes with a regression test. Its post-mortem hands off to **`/improve-codebase-architecture`** when the real finding is that there's no good seam to lock the bug down.
 
-- **A huge, foggy effort — a greenfield project or a huge feature build, too big for one session** → **`/wayfinder`**, the most cognitively demanding flow here. When the way from here to the destination isn't visible yet, it charts a **shared map** of investigation tickets on the issue tracker and resolves them one at a time — producing **decisions, not deliverables** — until the fog is pushed back and the way is clear. Where **`/grill-with-docs`** sharpens an idea you can hold in one session, wayfinder is for the idea you can't — and it's slower and denser, so save it for exactly that, never a well-scoped feature.
-
-  When the map clears, **it hands off, it doesn't build**: merge onto the main flow at **`/to-spec`**, which collapses the map's linked decisions into a buildable plan, then `/to-tickets` and `/implement` as usual. Looping the map straight into `/implement` skips that collapse and throws the linked detail away — go straight to `/implement` only when the effort turned out genuinely small.
+- **A huge, foggy effort — a greenfield project or a huge feature build, too big for one session** → **`/wayfinder`**. When the way from here to the destination isn't visible yet, it charts a **shared map** of investigation tickets on the issue tracker and resolves them one at a time — producing **decisions, not deliverables** — until the fog is pushed back and the way is clear. Then it merges onto the main flow at **`/to-spec`** (or, if the effort turned out small enough, straight to **`/implement`**). Where **`/grill-with-docs`** sharpens an idea you can hold in one session, wayfinder is for the idea you can't.
 
 ## Codebase health