diff --git a/templates/scripts/agent-file-locks.py b/templates/scripts/agent-file-locks.py
index f563747..b078210 100755
--- a/templates/scripts/agent-file-locks.py
+++ b/templates/scripts/agent-file-locks.py
@@ -210,8 +210,13 @@ def staged_changes(repo_root: Path) -> list[tuple[str, str]]:
 
 
 def list_worktree_roots(repo_root: Path) -> list[Path]:
-    """Every worktree path for this repo (porcelain). Falls back to [repo_root]
-    when git cannot enumerate, so single-checkout behavior is unchanged."""
+    """Every worktree path for this repo (porcelain), ALWAYS including the
+    caller's own repo_root. Submodules checked out inside a LINKED worktree
+    report their gitdir (<parent>/.git/worktrees/<wt>/modules/<sub>) as the
+    worktree path, not the actual working tree — repo_root (resolved via
+    --show-toplevel) is where claims are written, so it must be in the list
+    or claim/validate/status never see this checkout's own lock file. Falls
+    back to [repo_root] when git cannot enumerate."""
     try:
         out = run_git(['worktree', 'list', '--porcelain'], cwd=repo_root)
     except LockError:
@@ -221,7 +226,9 @@ def list_worktree_roots(repo_root: Path) -> list[Path]:
     for line in out.splitlines():
         if line.startswith('worktree '):
             roots.append(Path(line[len('worktree '):].strip()).resolve())
-    return roots or [repo_root]
+    if repo_root not in roots:
+        roots.append(repo_root)
+    return roots
 
 
 def load_all_locks(repo_root: Path) -> dict[str, list[dict[str, Any]]]:
diff --git a/test/agent-file-locks.test.js b/test/agent-file-locks.test.js
index a9cab4d..1d61474 100644
--- a/test/agent-file-locks.test.js
+++ b/test/agent-file-locks.test.js
@@ -168,6 +168,36 @@ defineSpawnSuite('agent-file-locks cross-worktree (G2)', () => {
     assert.match(v1.stderr, /another owner/);
   });
 
+  test('claims in a submodule under a LINKED worktree are visible to validate (gitdir-root quirk)', () => {
+    // A submodule checked out inside a linked worktree reports its gitdir
+    // (<parent>/.git/worktrees/<wt>/modules/<sub>) as the worktree path in
+    // `git worktree list`, so load_all_locks used to miss the REAL working
+    // tree's lock file — validate rejected claims it had just recorded.
+    const subSrc = makeRepo();
+    const parent = makeRepo();
+    assert.equal(
+      runHumanCmd('git', ['-c', 'protocol.file.allow=always', 'submodule', 'add', subSrc, 'sub'], parent).status,
+      0,
+      'submodule add must succeed',
+    );
+    assert.equal(runHumanCmd('git', ['commit', '-m', 'add submodule'], parent).status, 0);
+
+    const wtSub = path.join(parent, '..', 'wt-sub');
+    assert.equal(runHumanCmd('git', ['worktree', 'add', '-q', '-b', 'agent/sub/lane', wtSub], parent).status, 0);
+    assert.equal(
+      runHumanCmd('git', ['-c', 'protocol.file.allow=always', 'submodule', 'update', '--init'], wtSub).status,
+      0,
+      'submodule init inside the linked worktree must succeed',
+    );
+
+    const subWt = path.join(wtSub, 'sub');
+    writeFile(subWt, 'sub-file.txt');
+    assert.equal(locksAt(subWt, ['claim', '--branch', 'agent/sub/lane', 'sub-file.txt']).status, 0);
+
+    const v = locksAt(subWt, ['validate', '--branch', 'agent/sub/lane', 'sub-file.txt']);
+    assert.equal(v.status, 0, `validate must see the claim it just wrote: ${v.stderr}`);
+  });
+
   test('a lane can still claim + commit a file no other worktree owns', () => {
     const repoDir = makeRepo();
     writeFile(repoDir, 'mine.txt');