Resolve external targets from their own repository

Scope explicit sibling targets to their own Git root so caller context and hook manifests cannot suppress required detector guidance.

AI assistance disclosure: This commit was prepared with Codex under maintainer direction.

skill/scripts/context.mjs

@@ -208,6 +208,18 @@ function resolveProject(cwd = process.cwd(), options = {}) {
     }
   }
   if (!repoRoot) {
+    const targetIsExternal = hasTargetOption(options)
+      && targetDir !== absCwd
+      && !isPathInside(targetDir, absCwd);
+    if (targetIsExternal) {
+      const targetRepoRoot = findGitBoundaryRoot(targetDir) || targetDir;
+      return {
+        targetDir,
+        projectRoot: nearestTargetContextRoot(targetRepoRoot, targetDir) || targetRepoRoot,
+        repoRoot: targetRepoRoot,
+        isMonorepo: false,
+      };
+    }
     return {
       targetDir,
       projectRoot: nearestTargetContextRoot(absCwd, targetDir) || absCwd,
@@ -223,6 +235,18 @@ function resolveProject(cwd = process.cwd(), options = {}) {
   };
 }
 
+function findGitBoundaryRoot(startDir) {
+  let dir = path.resolve(startDir);
+  const homeDir = path.resolve(os.homedir());
+  while (true) {
+    if (hasGitBoundary(dir)) return dir;
+    if (dir === homeDir) return null;
+    const parent = path.dirname(dir);
+    if (parent === dir) return null;
+    dir = parent;
+  }
+}
+
 function isPathInside(candidate, root) {
   const rel = path.relative(root, candidate);
   return !!rel && !rel.startsWith('..') && !path.isAbsolute(rel);

tests/context.test.mjs

@@ -1298,6 +1298,40 @@ describe('context.mjs CLI', () => {
     assert.match(res.stdout, /MANUAL_DETECTOR_REQUIRED:/);
   });
 
+  it('does not borrow the caller hook for a target in an independent sibling repository', () => {
+    const scripts = path.join(scratch, 'bundle', 'skills', 'impeccable', 'scripts');
+    stageContextBundle(scripts, { providerId: 'claude-code' });
+
+    const caller = path.join(scratch, 'caller');
+    const target = path.join(scratch, 'target');
+    fs.mkdirSync(path.join(caller, '.git'), { recursive: true });
+    fs.mkdirSync(path.join(caller, '.claude'), { recursive: true });
+    fs.mkdirSync(path.join(target, '.git'), { recursive: true });
+    fs.mkdirSync(path.join(target, 'src'), { recursive: true });
+    fs.writeFileSync(path.join(caller, 'PRODUCT.md'), '# Caller\n');
+    fs.writeFileSync(path.join(caller, '.claude', 'settings.local.json'), JSON.stringify({
+      hooks: { Stop: [{ hooks: [{ command: 'node .claude/skills/impeccable/scripts/hook.mjs' }] }] },
+    }));
+    fs.writeFileSync(path.join(target, 'PRODUCT.md'), '# Target\n');
+    fs.writeFileSync(path.join(target, 'src', 'App.jsx'), 'export default function App() { return "target"; }\n');
+
+    const res = spawnSync(process.execPath, [
+      path.join(scripts, 'context.mjs'),
+      '--target',
+      path.join('..', 'target', 'src', 'App.jsx'),
+    ], {
+      cwd: caller,
+      encoding: 'utf8',
+      env: { ...process.env, IMPECCABLE_NO_UPDATE_CHECK: '1', IMPECCABLE_NO_STALENESS_CHECK: '1' },
+    });
+    assert.equal(res.status, 0, res.stderr);
+    assert.match(res.stdout, /"projectRoot": ".*\/target"/);
+    assert.match(res.stdout, /"repoRoot": ".*\/target"/);
+    assert.match(res.stdout, /# Target/);
+    assert.doesNotMatch(res.stdout, /# Caller/);
+    assert.match(res.stdout, /MANUAL_DETECTOR_REQUIRED:/);
+  });
+
   it('adds no detector directive when a per-edit-only hook is active', () => {
     const scripts = path.join(scratch, 'bundle', 'skills', 'impeccable', 'scripts');
     stageContextBundle(scripts, { providerId: 'cursor' });