fix(hooks): SessionStart SKILL.md path off-by-one

Hook lives at <plugin_root>/src/hooks/ but read SKILL.md via a single
'..' — resolving to nonexistent src/skills/, so every plugin install
silently fell back to the stale hardcoded ruleset (missing language
preservation, no-self-reference, intensity table).

Resolve via candidates in order: $CLAUDE_PLUGIN_ROOT/skills/,
__dirname/../../skills/ (plugin + repo layout), __dirname/../skills/
(standalone $CLAUDE_CONFIG_DIR layout). Sync the two missing rules
into the fallback for installs with no SKILL.md at all.

Fixes #587, fixes #589

src/hooks/caveman-activate.js

@@ -48,14 +48,32 @@ if (INDEPENDENT_MODES.has(mode)) {
 const modeLabel = mode === 'wenyan' ? 'wenyan-full' : mode;
 
 // Read SKILL.md — the single source of truth for caveman behavior.
-// Plugin installs: __dirname = <plugin_root>/hooks/, SKILL.md at <plugin_root>/skills/caveman/SKILL.md
-// Standalone installs: __dirname = $CLAUDE_CONFIG_DIR/hooks/, SKILL.md won't exist — falls back to hardcoded rules.
+// Candidate locations, tried in order (#587/#589 — the old single '..' path
+// resolved to <plugin_root>/src/skills/, which doesn't exist, so plugin
+// installs silently used the stale fallback ruleset):
+//   1. $CLAUDE_PLUGIN_ROOT/skills/caveman/SKILL.md — Claude Code sets
+//      CLAUDE_PLUGIN_ROOT when invoking plugin hooks; authoritative when present.
+//   2. ../../skills/caveman/SKILL.md — hook at <plugin_root>/src/hooks/
+//      (plugin.json layout) or a repo checkout.
+//   3. ../skills/caveman/SKILL.md — standalone install with hooks at
+//      $CLAUDE_CONFIG_DIR/hooks/ and the skill at $CLAUDE_CONFIG_DIR/skills/caveman/.
+// All misses fall through to the hardcoded fallback ruleset below.
+const skillCandidates = [];
+if (process.env.CLAUDE_PLUGIN_ROOT) {
+  skillCandidates.push(path.join(process.env.CLAUDE_PLUGIN_ROOT, 'skills', 'caveman', 'SKILL.md'));
+}
+skillCandidates.push(
+  path.join(__dirname, '..', '..', 'skills', 'caveman', 'SKILL.md'),
+  path.join(__dirname, '..', 'skills', 'caveman', 'SKILL.md')
+);
+
 let skillContent = '';
-try {
-  skillContent = fs.readFileSync(
-    path.join(__dirname, '..', 'skills', 'caveman', 'SKILL.md'), 'utf8'
-  );
-} catch (e) { /* standalone install — will use fallback below */ }
+for (const candidate of skillCandidates) {
+  try {
+    skillContent = fs.readFileSync(candidate, 'utf8');
+    break;
+  } catch (e) { /* try next candidate */ }
+}
 
 let output;
 
@@ -101,6 +119,8 @@ if (skillContent) {
     '## Rules\n\n' +
     'Drop: articles (a/an/the), filler (just/really/basically/actually/simply), pleasantries (sure/certainly/of course/happy to), hedging. ' +
     'Fragments OK. Short synonyms (big not extensive, fix not "implement a solution for"). Technical terms exact. Code blocks unchanged. Errors quoted exact.\n\n' +
+    "Preserve user's dominant language. User write Portuguese → reply Portuguese caveman. Compress the style, not the language. Technical terms, code, API names, commands, error strings stay verbatim.\n\n" +
+    'No self-reference. Never name or announce the style. No "caveman mode on" tags. Output caveman-only.\n\n' +
     'Pattern: `[thing] [action] [reason]. [next step].`\n\n' +
     'Not: "Sure! I\'d be happy to help you with that. The issue you\'re experiencing is likely caused by..."\n' +
     'Yes: "Bug in auth middleware. Token expiry check use `<` not `<=`. Fix:"\n\n' +

tests/test_hooks.py

@@ -1,5 +1,6 @@
 import json
 import os
+import shutil
 import subprocess
 import tempfile
 import unittest
@@ -10,10 +11,13 @@ REPO_ROOT = Path(__file__).resolve().parent.parent
 
 
 class HookScriptTests(unittest.TestCase):
-    def run_cmd(self, cmd, home):
+    def run_cmd(self, cmd, home, extra_env=None):
         env = os.environ.copy()
+        env.pop("CLAUDE_PLUGIN_ROOT", None)
         env["HOME"] = str(home)
         env["USERPROFILE"] = str(home)
+        if extra_env:
+            env.update(extra_env)
         return subprocess.run(
             cmd,
             cwd=REPO_ROOT,
@@ -156,6 +160,60 @@ class HookScriptTests(unittest.TestCase):
             self.assertNotIn("STATUSLINE SETUP NEEDED", result.stdout)
             self.assertEqual((claude_dir / ".caveman-active").read_text(), "full")
 
+    # Regression for #587/#589 — hook at <root>/src/hooks/ must resolve SKILL.md
+    # at <root>/skills/caveman/, not the nonexistent <root>/src/skills/.
+    def test_activate_emits_skill_md_not_fallback_from_repo_layout(self):
+        with tempfile.TemporaryDirectory(prefix="caveman-hooks-skillpath-") as tmp:
+            home = Path(tmp)
+            (home / ".claude").mkdir(parents=True)
+
+            result = self.run_cmd(["node", "src/hooks/caveman-activate.js"], home)
+
+            # Intensity table exists only in SKILL.md, never in the fallback
+            self.assertIn("## Intensity", result.stdout)
+            # Default mode is full — table filtered to the active level's row
+            self.assertIn("| **full** |", result.stdout)
+            self.assertNotIn("| **lite** |", result.stdout)
+
+    def test_activate_finds_skill_beside_config_dir_hooks(self):
+        # Standalone layout: hooks at $CLAUDE_CONFIG_DIR/hooks/, skill installed
+        # at $CLAUDE_CONFIG_DIR/skills/caveman/SKILL.md
+        with tempfile.TemporaryDirectory(prefix="caveman-hooks-standalone-") as tmp:
+            home = Path(tmp)
+            claude_dir = home / ".claude"
+            hooks_dir = claude_dir / "hooks"
+            hooks_dir.mkdir(parents=True)
+            for name in ("caveman-activate.js", "caveman-config.js", "package.json"):
+                shutil.copy(REPO_ROOT / "src" / "hooks" / name, hooks_dir / name)
+            skill_dir = claude_dir / "skills" / "caveman"
+            skill_dir.mkdir(parents=True)
+            (skill_dir / "SKILL.md").write_text(
+                "---\nname: caveman\n---\nSTANDALONE MARKER RULESET\n"
+            )
+
+            result = self.run_cmd(["node", str(hooks_dir / "caveman-activate.js")], home)
+
+            self.assertIn("STANDALONE MARKER RULESET", result.stdout)
+
+    def test_activate_prefers_claude_plugin_root(self):
+        with tempfile.TemporaryDirectory(prefix="caveman-hooks-pluginroot-") as tmp:
+            home = Path(tmp)
+            (home / ".claude").mkdir(parents=True)
+            plugin_root = home / "plugin-cache"
+            skill_dir = plugin_root / "skills" / "caveman"
+            skill_dir.mkdir(parents=True)
+            (skill_dir / "SKILL.md").write_text(
+                "---\nname: caveman\n---\nPLUGIN ROOT MARKER RULESET\n"
+            )
+
+            result = self.run_cmd(
+                ["node", "src/hooks/caveman-activate.js"],
+                home,
+                extra_env={"CLAUDE_PLUGIN_ROOT": str(plugin_root)},
+            )
+
+            self.assertIn("PLUGIN ROOT MARKER RULESET", result.stdout)
+
 
 if __name__ == "__main__":
     unittest.main()