What

Adds hooks/package.json with { "type": "commonjs" } so the caveman hooks resolve as CJS regardless of what the user's ~/.claude/package.json declares. Also registers the new file in install.{sh,ps1} and uninstall.{sh,ps1} so standalone installs (curl | bash / PowerShell) copy it into ~/.claude/hooks/.

Why

When ~/.claude/package.json (or any ancestor) contains "type": "module", Node treats every .js file under that tree as an ES module. The caveman hooks are CommonJS (require('fs')), so they crash immediately:

ReferenceError: require is not defined in ES module scope
    at file:///.../hooks/caveman-activate.js:9:12

surfaced to the user as:

SessionStart:clear hook error
Failed with non-blocking status code: file:///.../caveman-activate.js:9
UserPromptSubmit hook error
Failed with non-blocking status code: file:///.../caveman-mode-tracker.js:5

Repros on any user who has { "type": "module" } in ~/.claude/package.json — which several Claude Code plugins/skills set up. On my machine this stopped both hooks from firing (flag file not written, ruleset never injected, statusline badge missing).

The ESM sub-case is flagged in @mrx-arafat's comment on #167 — recommending exactly this workaround but applied by the user, not shipped by the plugin. Shipping it here means the fix survives plugin updates and reaches every install without user action.

How the fix works

Node's module-type resolution walks up looking for the nearest package.json. By dropping one into hooks/ itself, we pin the directory to CJS regardless of any ancestor settings. Zero code changes to the hooks themselves.

Resolution order:

• Before: ~/.claude/package.json → "type": "module" → .js treated as ESM → require undefined → crash.
• After: hooks/package.json (nearer ancestor) → "type": "commonjs" → .js treated as CJS → hook runs.

Scope note

This does not fix the Windows ${CLAUDE_PLUGIN_ROOT} path-expansion issues with spaces/umlauts in #167 / #78 / #72 — those have a separate root cause (unquoted variable in plugin.json) and need their own patch.

Verification

Simulated ESM-parent environment:

mkdir -p /tmp/esm-test/.claude/plugins/hooks
echo '{"type":"module"}' > /tmp/esm-test/.claude/package.json
cp hooks/{package.json,caveman-config.js,caveman-activate.js,caveman-mode-tracker.js} \
   /tmp/esm-test/.claude/plugins/hooks/

HOME=/tmp/esm-test node /tmp/esm-test/.claude/plugins/hooks/caveman-activate.js
# → exit 0, emits "CAVEMAN MODE ACTIVE — level: full" + ruleset

echo '{"prompt":"hi"}' | HOME=/tmp/esm-test \
  node /tmp/esm-test/.claude/plugins/hooks/caveman-mode-tracker.js
# → exit 0

Without the fix both commands fail with ReferenceError: require is not defined in ES module scope.

Files changed

• hooks/package.json (new) — { "type": "commonjs" }
• hooks/install.sh — add package.json to HOOK_FILES
• hooks/install.ps1 — add package.json to $HookFiles
• hooks/uninstall.sh — add package.json to HOOK_FILES
• hooks/uninstall.ps1 — add package.json to $HookFiles