diff --git a/careful/SKILL.md b/careful/SKILL.md
index 678d66c16b..8887400927 100644
--- a/careful/SKILL.md
+++ b/careful/SKILL.md
@@ -14,7 +14,7 @@ hooks:
     - matcher: "Bash"
       hooks:
         - type: command
-          command: "bash ${CLAUDE_SKILL_DIR}/bin/check-careful.sh"
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/careful/bin/check-careful.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/careful/bin/check-careful.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking for destructive commands..."
 ---
 <!-- AUTO-GENERATED from SKILL.md.tmpl — do not edit directly -->
diff --git a/careful/SKILL.md.tmpl b/careful/SKILL.md.tmpl
index 9d83411f83..19bf04f191 100644
--- a/careful/SKILL.md.tmpl
+++ b/careful/SKILL.md.tmpl
@@ -19,7 +19,7 @@ hooks:
     - matcher: "Bash"
       hooks:
         - type: command
-          command: "bash ${CLAUDE_SKILL_DIR}/bin/check-careful.sh"
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/careful/bin/check-careful.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/careful/bin/check-careful.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking for destructive commands..."
 sensitive: true
 ---
diff --git a/freeze/SKILL.md b/freeze/SKILL.md
index fc82b1bea8..18c5c0fea6 100644
--- a/freeze/SKILL.md
+++ b/freeze/SKILL.md
@@ -15,12 +15,12 @@ hooks:
     - matcher: "Edit"
       hooks:
         - type: command
-          command: "bash ${CLAUDE_SKILL_DIR}/bin/check-freeze.sh"
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking freeze boundary..."
     - matcher: "Write"
       hooks:
         - type: command
-          command: "bash ${CLAUDE_SKILL_DIR}/bin/check-freeze.sh"
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking freeze boundary..."
 ---
 <!-- AUTO-GENERATED from SKILL.md.tmpl — do not edit directly -->
diff --git a/freeze/SKILL.md.tmpl b/freeze/SKILL.md.tmpl
index a1b456e535..7cf3b90cfc 100644
--- a/freeze/SKILL.md.tmpl
+++ b/freeze/SKILL.md.tmpl
@@ -20,12 +20,12 @@ hooks:
     - matcher: "Edit"
       hooks:
         - type: command
-          command: "bash ${CLAUDE_SKILL_DIR}/bin/check-freeze.sh"
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking freeze boundary..."
     - matcher: "Write"
       hooks:
         - type: command
-          command: "bash ${CLAUDE_SKILL_DIR}/bin/check-freeze.sh"
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking freeze boundary..."
 sensitive: true
 ---
diff --git a/guard/SKILL.md b/guard/SKILL.md
index e4dff7936f..7680fc3bc8 100644
--- a/guard/SKILL.md
+++ b/guard/SKILL.md
@@ -15,17 +15,17 @@ hooks:
     - matcher: "Bash"
       hooks:
         - type: command
-          command: "bash ${CLAUDE_SKILL_DIR}/../careful/bin/check-careful.sh"
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/careful/bin/check-careful.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/careful/bin/check-careful.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking for destructive commands..."
     - matcher: "Edit"
       hooks:
         - type: command
-          command: "bash ${CLAUDE_SKILL_DIR}/../freeze/bin/check-freeze.sh"
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking freeze boundary..."
     - matcher: "Write"
       hooks:
         - type: command
-          command: "bash ${CLAUDE_SKILL_DIR}/../freeze/bin/check-freeze.sh"
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking freeze boundary..."
 ---
 <!-- AUTO-GENERATED from SKILL.md.tmpl — do not edit directly -->
diff --git a/guard/SKILL.md.tmpl b/guard/SKILL.md.tmpl
index 5829dbe48f..c006b7f99b 100644
--- a/guard/SKILL.md.tmpl
+++ b/guard/SKILL.md.tmpl
@@ -20,17 +20,17 @@ hooks:
     - matcher: "Bash"
       hooks:
         - type: command
-          command: "bash ${CLAUDE_SKILL_DIR}/../careful/bin/check-careful.sh"
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/careful/bin/check-careful.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/careful/bin/check-careful.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking for destructive commands..."
     - matcher: "Edit"
       hooks:
         - type: command
-          command: "bash ${CLAUDE_SKILL_DIR}/../freeze/bin/check-freeze.sh"
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking freeze boundary..."
     - matcher: "Write"
       hooks:
         - type: command
-          command: "bash ${CLAUDE_SKILL_DIR}/../freeze/bin/check-freeze.sh"
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking freeze boundary..."
 sensitive: true
 ---
diff --git a/investigate/SKILL.md b/investigate/SKILL.md
index 9431b58f6e..abfd6f280c 100644
--- a/investigate/SKILL.md
+++ b/investigate/SKILL.md
@@ -23,12 +23,12 @@ hooks:
     - matcher: "Edit"
       hooks:
         - type: command
-          command: 'bash -c ''S="${CLAUDE_SKILL_DIR}/../freeze/bin/check-freeze.sh"; [ -x "$S" ] || S="${CLAUDE_SKILL_DIR}/../gstack-freeze/bin/check-freeze.sh"; [ -x "$S" ] && bash "$S" || exit 0'''
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking debug scope boundary..."
     - matcher: "Write"
       hooks:
         - type: command
-          command: 'bash -c ''S="${CLAUDE_SKILL_DIR}/../freeze/bin/check-freeze.sh"; [ -x "$S" ] || S="${CLAUDE_SKILL_DIR}/../gstack-freeze/bin/check-freeze.sh"; [ -x "$S" ] && bash "$S" || exit 0'''
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking debug scope boundary..."
 gbrain:
   schema: 1
diff --git a/investigate/SKILL.md.tmpl b/investigate/SKILL.md.tmpl
index 67e254d743..8cc51db1bf 100644
--- a/investigate/SKILL.md.tmpl
+++ b/investigate/SKILL.md.tmpl
@@ -30,12 +30,12 @@ hooks:
     - matcher: "Edit"
       hooks:
         - type: command
-          command: 'bash -c ''S="${CLAUDE_SKILL_DIR}/../freeze/bin/check-freeze.sh"; [ -x "$S" ] || S="${CLAUDE_SKILL_DIR}/../gstack-freeze/bin/check-freeze.sh"; [ -x "$S" ] && bash "$S" || exit 0'''
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking debug scope boundary..."
     - matcher: "Write"
       hooks:
         - type: command
-          command: 'bash -c ''S="${CLAUDE_SKILL_DIR}/../freeze/bin/check-freeze.sh"; [ -x "$S" ] || S="${CLAUDE_SKILL_DIR}/../gstack-freeze/bin/check-freeze.sh"; [ -x "$S" ] && bash "$S" || exit 0'''
+          command: 'bash -c ''D="$PWD"; while :; do S="$D/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; [ "$D" = "/" ] && break; D="$(dirname "$D")"; done; S="$HOME/.claude/skills/gstack/freeze/bin/check-freeze.sh"; [ -x "$S" ] && exec bash "$S"; exit 0'''
           statusMessage: "Checking debug scope boundary..."
 gbrain:
   schema: 1
diff --git a/test/gen-skill-docs.test.ts b/test/gen-skill-docs.test.ts
index 3554094ca5..ba8bd9af39 100644
--- a/test/gen-skill-docs.test.ts
+++ b/test/gen-skill-docs.test.ts
@@ -1837,7 +1837,7 @@ describe('Codex generation (--host codex)', () => {
     expect(frontmatter).toContain('YC Office Hours');
   });
 
-  test('hook skills have safety prose and no hooks: in frontmatter', () => {
+  test('Codex hook skills have safety prose and no hooks: in frontmatter', () => {
     const HOOK_SKILLS = ['gstack-careful', 'gstack-freeze', 'gstack-guard'];
     for (const skillName of HOOK_SKILLS) {
       const content = fs.readFileSync(path.join(AGENTS_DIR, skillName, 'SKILL.md'), 'utf-8');
@@ -1850,6 +1850,59 @@ describe('Codex generation (--host codex)', () => {
     }
   });
 
+  test('Claude hook commands do not depend on CLAUDE_SKILL_DIR', () => {
+    // #1871: Claude Code 2.1.162 does not populate CLAUDE_SKILL_DIR for
+    // skill-frontmatter PreToolUse hooks. If these commands use that variable,
+    // they expand to paths like /../freeze/bin/check-freeze.sh and fail before
+    // the safety hook can do its job.
+    const HOOK_SKILLS = ['careful', 'freeze', 'guard', 'investigate'];
+    for (const skillName of HOOK_SKILLS) {
+      const content = fs.readFileSync(path.join(ROOT, skillName, 'SKILL.md'), 'utf-8');
+      const fmEnd = content.indexOf('\n---', 4);
+      const frontmatter = content.slice(4, fmEnd);
+      expect(frontmatter).toContain('hooks:');
+      expect(frontmatter).not.toContain('CLAUDE_SKILL_DIR');
+      expect(frontmatter).not.toContain('CLAUDE_PLUGIN_ROOT');
+      expect(frontmatter).not.toContain('git rev-parse --show-toplevel');
+      expect(frontmatter).toContain('while :; do');
+      expect(frontmatter).toContain('$D/.claude/skills/gstack/');
+      expect(frontmatter).toContain('$HOME/.claude/skills/gstack/');
+    }
+  });
+
+  test('Claude hook commands resolve project-local install from nested non-git cwd', () => {
+    const { execFileSync } = require('child_process');
+    const tmpRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'gstack-hook-local-'));
+    const projectRoot = path.join(tmpRoot, 'project');
+    const nestedCwd = path.join(projectRoot, 'nested', 'plain-dir');
+    const scriptPath = path.join(projectRoot, '.claude', 'skills', 'gstack', 'careful', 'bin', 'check-careful.sh');
+
+    fs.mkdirSync(path.dirname(scriptPath), { recursive: true });
+    fs.mkdirSync(nestedCwd, { recursive: true });
+    fs.writeFileSync(scriptPath, '#!/usr/bin/env bash\nprintf local-careful');
+    fs.chmodSync(scriptPath, 0o755);
+
+    try {
+      const content = fs.readFileSync(path.join(ROOT, 'careful', 'SKILL.md'), 'utf-8');
+      const fmEnd = content.indexOf('\n---', 4);
+      const frontmatter = content.slice(4, fmEnd);
+      const commandLine = frontmatter.split('\n').find(line => line.trim().startsWith('command: '));
+      expect(commandLine).toBeTruthy();
+      let command = commandLine!.trim().slice('command: '.length);
+      expect(command.startsWith("'")).toBe(true);
+      command = command.slice(1, -1).replaceAll("''", "'");
+
+      const output = execFileSync('bash', ['-c', command], {
+        cwd: nestedCwd,
+        input: '{}',
+        encoding: 'utf8',
+      });
+      expect(output).toBe('local-careful');
+    } finally {
+      fs.rmSync(tmpRoot, { recursive: true, force: true });
+    }
+  });
+
   test('all Codex SKILL.md files have auto-generated header', () => {
     for (const skill of CODEX_SKILLS) {
       const content = fs.readFileSync(path.join(AGENTS_DIR, skill.codexName, 'SKILL.md'), 'utf-8');