feat: ship a Claude Code plugin that finds and bwraps the checker

.changeset/claude-plugin.md

@@ -0,0 +1,5 @@
+---
+'@systemfsoftware/claude-code-comment-checker': minor
+---
+
+This repository is also a Claude Code plugin. Enabling it runs a PostToolUse hook that tries `comment-checker --strip`, then `direnv exec`. If both miss and the project has `flake.nix`, the error tells you to run `direnv allow` or `nix develop`.

.claude-plugin/plugin.json

@@ -0,0 +1,13 @@
+{
+  "name": "comment-checker",
+  "version": "0.2.0",
+  "description": "PostToolUse hook that flags unnecessary comments. Runs comment-checker --strip, then direnv exec if it is missing. Names flake.nix when that is why it is missing.",
+  "author": {
+    "name": "systemfsoftware",
+    "url": "https://github.com/systemfsoftware/comment-checker"
+  },
+  "homepage": "https://github.com/systemfsoftware/comment-checker",
+  "repository": "https://github.com/systemfsoftware/comment-checker",
+  "license": "Apache-2.0",
+  "keywords": ["hooks", "comments", "claude-code"]
+}

README.md

@@ -67,6 +67,12 @@ Add the hook to user (`~/.claude/settings.json`) or project (`.claude/settings.j
 }
 ```
 
+Or install this repo as a Claude Code plugin. The hook runs `comment-checker --strip`, then `direnv exec` if that binary is missing. A `flake.nix` in the project makes the error tell you to `direnv allow` or `nix develop` (the flake wraps the checker in bwrap). Deno must be on PATH.
+
+```bash
+claude --plugin-dir .
+```
+
 On `Edit` and `MultiEdit`, only the comments *added* by the edit are checked — pre-existing comments are left alone. Edits also arrive as fragments, so restatement detection is disabled on them to avoid false positives.
 
 ### Verify the wiring

hooks/deno.jsonc

@@ -0,0 +1,9 @@
+{
+  "lock": "./deno.lock",
+  "imports": {
+    "@std/fs": "jsr:@std/fs@1.0.19",
+    "@std/io": "jsr:@std/io@0.225.2",
+    "@std/path": "jsr:@std/path@1.1.6",
+    "arktype": "npm:arktype@2.2.3"
+  }
+}

hooks/hooks.json

@@ -0,0 +1,14 @@
+{
+  "PostToolUse": [
+    {
+      "matcher": "Write|Edit|MultiEdit",
+      "hooks": [
+        {
+          "type": "command",
+          "command": "\"${CLAUDE_PLUGIN_ROOT}/hooks/run.ts\"",
+          "timeout": 30
+        }
+      ]
+    }
+  ]
+}

hooks/run.ts

@@ -0,0 +1,61 @@
+#!/usr/bin/env -S deno run --allow-read --allow-run=comment-checker,direnv --allow-env=CLAUDE_PROJECT_DIR,PATH,HOME
+
+import { exists } from '@std/fs/exists'
+import { writeAll } from '@std/io/write-all'
+import { join } from '@std/path'
+import { type } from 'arktype'
+
+const Env = type({
+  CLAUDE_PROJECT_DIR: type('string.trim').pipe(type('string').atLeastLength(1)),
+})
+
+const env = Env({
+  CLAUDE_PROJECT_DIR: Deno.env.get('CLAUDE_PROJECT_DIR') ?? '',
+})
+
+if (env instanceof type.errors) {
+  await writeAll(
+    Deno.stderr,
+    new TextEncoder().encode(`CLAUDE_PROJECT_DIR must be set by the hook host\n${env.summary}\n`),
+  )
+  Deno.exit(1)
+}
+
+async function run(cmd: string, args: string[]): Promise<number | undefined> {
+  try {
+    const { code } = await new Deno.Command(cmd, {
+      args,
+      stdin: 'inherit',
+      stdout: 'inherit',
+      stderr: 'inherit',
+    }).output()
+    return code
+  } catch (error) {
+    if (error instanceof Deno.errors.NotFound) return undefined
+    throw error
+  }
+}
+
+const strip = ['--strip']
+const projectDir = env.CLAUDE_PROJECT_DIR
+
+const fromPath = await run('comment-checker', strip)
+if (fromPath !== undefined) Deno.exit(fromPath)
+
+const fromDirenv = await run('direnv', ['exec', projectDir, 'comment-checker', ...strip])
+if (fromDirenv !== undefined) Deno.exit(fromDirenv)
+
+const flake = await exists(join(projectDir, 'flake.nix'))
+await writeAll(
+  Deno.stderr,
+  new TextEncoder().encode(
+    [
+      'comment-checker did not run, so nothing checked this write.',
+      flake
+        ? 'This project has flake.nix. Run direnv allow or nix develop so comment-checker is on PATH (the flake wraps it in bwrap).'
+        : 'Install it: pnpm add -g @systemfsoftware/claude-code-comment-checker',
+      '',
+    ].join('\n'),
+  ),
+)
+Deno.exit(1)