diff --git a/CHANGELOG.md b/CHANGELOG.md
index 236e78da..f7d6330c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- **Dirty install no longer reports "Up to date" with no remediation affordance (#4085).** The update check payload now carries a `dirty: bool` reflecting the working-tree state vs HEAD, so the Settings update panel can surface a "Local changes detected" state with an apply-latest action wired to the existing destructive-reset endpoint when the install is dirty and at-or-past the latest release tag.
+
 ## [v0.51.382] — 2026-06-13 — Release MU (Stable Assistant Turn Anchors: activity-scene projection, inert, #4093)
 
 ### Added
diff --git a/api/updates.py b/api/updates.py
index b1a62abe..e1215d4e 100644
--- a/api/updates.py
+++ b/api/updates.py
@@ -644,7 +644,14 @@ def _check_repo_branch(path, name, *, fetch=True):
 
 
 def _check_repo(path, name):
-    """Check if a git repo is behind its latest release. Returns dict or None."""
+    """Check if a git repo is behind its latest release. Returns dict or None.
+
+    The returned dict (when not None) always carries a ``dirty: bool`` reflecting
+    the working-tree state vs HEAD. A dirty install at-or-past the latest release
+    tag used to silently report "Up to date" with no remediation affordance, so
+    the Settings panel reads this flag to offer ``apply_force_update`` (issue
+    #4085).
+    """
     if path is None or not (path / '.git').exists():
         return None
 
@@ -667,19 +674,43 @@ def _check_repo(path, name):
             release_info = dict(release_info)
             release_info['error'] = message
             release_info['stale_check'] = True
+            release_info['dirty'] = _is_dirty(path)
             return release_info
         return {
             'name': name,
             'behind': None,
             'error': message,
             'stale_check': True,
+            'dirty': _is_dirty(path),
         }
 
     release_info = _check_repo_release(path, name)
     if release_info is not None:
+        release_info = dict(release_info)
+        release_info['dirty'] = _is_dirty(path)
         return release_info
 
-    return _check_repo_branch(path, name, fetch=False)
+    branch_info = _check_repo_branch(path, name, fetch=False)
+    if branch_info is not None:
+        branch_info = dict(branch_info)
+        branch_info['dirty'] = _is_dirty(path)
+        return branch_info
+    return None
+
+
+def _is_dirty(path: Path, timeout: int = 1) -> bool:
+    """Return True when the working tree has uncommitted changes vs HEAD.
+
+    Same primitive as ``_dirty_suffix`` (issue #4085): ``git diff-index
+    --quiet HEAD --`` exits 0 on a clean tree and 1 on a dirty tree (not an
+    error). Real errors (timeout, missing git, fatal) are conservatively
+    reported as clean so a transient probe failure never produces a false-
+    positive "local changes" alert.
+    """
+    out, ok = _run_git(['diff-index', '--quiet', 'HEAD', '--'], path, timeout=timeout)
+    if ok:
+        return False
+    return not out or out.startswith('git exited with status ')
 
 
 def _ignored_agent_update_info() -> dict:
diff --git a/tests/test_update_checker.py b/tests/test_update_checker.py
index 2e8733eb..82912de2 100644
--- a/tests/test_update_checker.py
+++ b/tests/test_update_checker.py
@@ -322,3 +322,34 @@ class TestApplyUpdateDiagnostics:
         assert 'could not reach' in result['message'].lower() or \
                'internet' in result['message'].lower() or \
                'remote' in result['message'].lower()
+
+
+# Issue #4085 regression: a dirty install at-or-past the latest release tag
+# must surface `dirty: True` on the check payload so the Settings panel can
+# offer `apply_force_update` instead of the silent "Up to date" state.
+class TestCheckRepoDirtyFlag:
+    def test_dirty_tree_surfaces_dirty_true(self, tmp_path):
+        """A dirty tree on a network-failed check must still carry dirty=True.
+
+        The Settings panel needs the dirty flag on every payload shape so a
+        user can always recover from a local-modifications state, even when
+        the latest remote cannot be reached.
+        """
+        (tmp_path / '.git').mkdir()
+
+        def fake_git(args, cwd, timeout=10):
+            if args == ['diff-index', '--quiet', 'HEAD', '--']:
+                return '', False  # dirty
+            if args == ['fetch', 'origin', '--tags', '--force']:
+                return 'network unavailable', False  # fail fast
+            if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
+                return '', True
+            raise AssertionError(f'unexpected git args: {args!r}')
+
+        from api import updates
+        with patch(f'{_MODULE}._run_git', side_effect=fake_git):
+            info = updates._check_repo(tmp_path, 'webui')
+
+        assert info is not None
+        assert info['dirty'] is True
+        assert info['stale_check'] is True
diff --git a/tests/test_updates.py b/tests/test_updates.py
index 3297ade4..0cadd897 100644
--- a/tests/test_updates.py
+++ b/tests/test_updates.py
@@ -5,6 +5,8 @@ import api.updates as updates
 
 
 def _fake_git_for_release_fetch_failure(args, cwd, timeout=10):
+    if args == ['diff-index', '--quiet', 'HEAD', '--']:
+        return '', True  # clean tree
     if args == ['fetch', 'origin', '--tags', '--force']:
         return 'would clobber existing tag v0.50.294', False
     if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
@@ -32,6 +34,9 @@ def test_check_repo_reports_release_gap_even_when_tag_fetch_fails(tmp_path):
     assert info['latest_version'] == 'v0.51.106'
     assert info['stale_check'] is True
     assert 'would clobber existing tag' in info['error']
+    # Issue #4085: the dirty flag must ride along on every payload shape.
+    # The mock returns ('', True) for the dirty probe, so the tree is clean.
+    assert info['dirty'] is False
 
 
 def test_check_repo_redacts_credentialed_fetch_failure(tmp_path):
@@ -45,6 +50,8 @@ def test_check_repo_redacts_credentialed_fetch_failure(tmp_path):
     )
 
     def fake_git(args, cwd, timeout=10):
+        if args == ['diff-index', '--quiet', 'HEAD', '--']:
+            return '', True
         if args == ['fetch', 'origin', '--tags', '--force']:
             return raw_error, False
         if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
@@ -68,6 +75,8 @@ def test_check_repo_fetch_failure_without_tags_is_not_up_to_date(tmp_path):
     (tmp_path / '.git').mkdir()
 
     def fake_git(args, cwd, timeout=10):
+        if args == ['diff-index', '--quiet', 'HEAD', '--']:
+            return '', True
         if args == ['fetch', 'origin', '--tags', '--force']:
             return 'network unavailable', False
         if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
@@ -225,6 +234,8 @@ def test_check_repo_fetches_tags_with_force(tmp_path):
 
     def fake_git(args, cwd, timeout=10):
         seen_args.append(args)
+        if args == ['diff-index', '--quiet', 'HEAD', '--']:
+            return '', True
         if args[:2] == ['fetch', 'origin']:
             # Force a fetch failure path so we don't have to mock the rest of
             # the release/branch logic; the assertion is about the args shape.