diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5244c587..a909f3eb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,16 @@
 
 ## [Unreleased]
 
+## [v0.51.427] — 2026-06-15 — Release ON (CLI sessions on by default for new installs #3988 + symlink delete/rename guard #4217)
+
+### Changed
+
+- **CLI / TUI / messaging sessions now appear in the sidebar by default for new installs (#3988).** `show_cli_sessions` now defaults to `True`, so sessions from the CLI, TUI, Telegram, Discord, and the Hermes One desktop app show up in the WebUI sidebar without users having to discover the toggle in Settings. **Existing installs are grandfathered:** a user who already completed onboarding and never opted in keeps their previous (hidden) behavior — the default change only affects fresh installs. The toggle remains in Settings → Sessions for anyone who wants to change it.
+
+### Fixed
+
+- **Deleting or renaming a workspace symlink no longer destroys the file or directory it points to (#4217).** `/api/file/delete` and `/api/file/rename` resolved the final symlink before operating on the target, so a standard delete/rename against a symlink name acted on the real (possibly out-of-workspace) target. Both handlers now reject a symlinked path with a 400, matching the guard the move handler already had. (#4217)
+
 ## [v0.51.426] — 2026-06-15 — Release OM (custom-provider model-prefix routing fix, #4210)
 
 ### Fixed
diff --git a/api/config.py b/api/config.py
index c0073975..2e648ce3 100644
--- a/api/config.py
+++ b/api/config.py
@@ -6505,7 +6505,7 @@ _SETTINGS_DEFAULTS = {
     "hide_empty_state_suggestions": False,  # hide the default new-chat suggestion buttons
     "show_tps": False,  # show tokens-per-second chip in assistant message headers
     "fade_text_effect": False,  # animate newly streamed words with a lightweight fade-in effect
-    "show_cli_sessions": False,  # merge CLI sessions from state.db into the sidebar
+    "show_cli_sessions": True,  # merge CLI/TUI/messaging sessions from state.db into the sidebar by default (#3988); established installs are grandfathered OFF by the load_settings backfill
     "show_cron_sessions": False,  # surface cron sessions in the sidebar (subordinate to show_cli_sessions)
     "show_previous_messaging_sessions": False,  # show older Telegram/Discord/etc. reset segments
     "sync_to_insights": False,  # mirror WebUI token usage to state.db for /insights
@@ -6647,6 +6647,26 @@ def load_settings() -> dict:
                         if k not in _SETTINGS_LEGACY_DROP_KEYS
                     }
                 )
+                # Grandfather established installs OFF for show_cli_sessions (#3988).
+                # The default flipped True so NEW users see CLI/TUI/messaging
+                # sessions without hunting for the toggle — but an existing user
+                # who never opted in should not have their sidebar silently change.
+                # Treat the install as established (and pin the old False default)
+                # when show_cli_sessions is absent AND the file already carries
+                # real user state — either onboarding was completed, or some
+                # setting OTHER than a not-yet-completed onboarding flag has been
+                # persisted. Keying on "has saved user state" (not just
+                # onboarding_completed) also covers a CLI-configured user who
+                # tweaked a WebUI setting before running the wizard. A genuinely
+                # new / still-mid-onboarding file falls through to the True default.
+                _established_keys = [
+                    k for k in stored
+                    if k not in ("show_cli_sessions", "onboarding_completed")
+                ]
+                if "show_cli_sessions" not in stored and (
+                    bool(stored.get("onboarding_completed")) or _established_keys
+                ):
+                    settings["show_cli_sessions"] = False
         except Exception:
             logger.debug("Failed to load settings from %s", SETTINGS_FILE)
     settings["theme"], settings["skin"] = _normalize_appearance(
diff --git a/api/routes.py b/api/routes.py
index 5e77372f..9daa71ff 100644
--- a/api/routes.py
+++ b/api/routes.py
@@ -14723,6 +14723,13 @@ def _handle_file_delete(handler, body):
     try:
         ws_root = Path(s.workspace)
         target = safe_resolve(ws_root, body["path"])
+        # Reject a symlinked entry BEFORE the follow-based exists() check: a
+        # dangling symlink resolves to a missing target, so an exists()-first
+        # order would misclassify it as 404 "File not found" and leave it
+        # permanently undeletable. is_symlink() is a no-follow lstat on the
+        # lexically-requested path, so it catches both live and dangling links.
+        if (ws_root / body["path"]).is_symlink():
+            return bad(handler, "Cannot delete a symlinked entry")
         if not target.exists():
             return bad(handler, "File not found", 404)
         if target.is_dir():
@@ -14803,6 +14810,11 @@ def _handle_file_rename(handler, body):
         ws_root = Path(s.workspace)
         ws_root_resolved = ws_root.resolve()
         source = safe_resolve(ws_root, body["path"])
+        # Reject a symlinked entry BEFORE the follow-based exists() check (see
+        # _handle_file_delete): a dangling symlink would otherwise 404 and stay
+        # unrenameable. is_symlink() is a no-follow lstat on the requested path.
+        if (ws_root / body["path"]).is_symlink():
+            return bad(handler, "Cannot rename a symlinked entry")
         if not source.exists():
             return bad(handler, "File not found", 404)
         new_name = body["new_name"].strip()
@@ -14838,15 +14850,18 @@ def _handle_file_move(handler, body):
         # returning a confusing 400 for a move that actually happened.
         ws_root_resolved = ws_root.resolve()
         source = safe_resolve(ws_root, body["path"])
-        if not source.exists():
-            return bad(handler, "File not found", 404)
-        # Reject a symlinked SOURCE entry. safe_resolve() follows the final
-        # symlink, so source.name/source.parent would point at the link's
-        # TARGET, not the dragged entry — moving link.txt would silently move
-        # dir/real.txt and leave link.txt dangling. Detect the symlink on the
-        # lexically-requested final component (lstat, no-follow) and refuse.
+        # Reject a symlinked SOURCE entry BEFORE the follow-based exists() check.
+        # safe_resolve() follows the final symlink, so source.name/source.parent
+        # would point at the link's TARGET, not the dragged entry — moving
+        # link.txt would silently move dir/real.txt and leave link.txt dangling.
+        # Detect the symlink on the lexically-requested final component (lstat,
+        # no-follow) and refuse; running this before exists() also means a
+        # dangling symlink is rejected (400) rather than misclassified as 404
+        # (matches the delete/rename ordering).
         if (ws_root / body["path"]).is_symlink():
             return bad(handler, "Cannot move a symlinked entry")
+        if not source.exists():
+            return bad(handler, "File not found", 404)
         dest_dir_raw = (body.get("dest_dir") or ".").strip()
         if not dest_dir_raw:
             dest_dir_raw = "."
diff --git a/static/boot.js b/static/boot.js
index 4c134d3f..da0f05dc 100644
--- a/static/boot.js
+++ b/static/boot.js
@@ -1848,7 +1848,7 @@ function applyBotName(){
     applyEmptyStateSuggestionPref();
     window._showTps=!!s.show_tps;
     window._fadeTextEffect=!!s.fade_text_effect;
-    window._showCliSessions=!!s.show_cli_sessions;
+    window._showCliSessions=s.show_cli_sessions!==false;
     window._showPreviousMessagingSessions=!!s.show_previous_messaging_sessions;
     window._soundEnabled=!!s.sound_enabled;
     window._notificationsEnabled=!!s.notifications_enabled;
@@ -1959,7 +1959,7 @@ function applyBotName(){
     applyEmptyStateSuggestionPref();
     window._showTps=false;
     window._fadeTextEffect=false;
-    window._showCliSessions=false;
+    window._showCliSessions=true;  // settings-load failed: mirror the True config default (#3988)
     window._soundEnabled=false;
     window._notificationsEnabled=false;
     window._whatsNewSummaryEnabled=false;
diff --git a/static/panels.js b/static/panels.js
index 4786db79..1e5dc259 100644
--- a/static/panels.js
+++ b/static/panels.js
@@ -6773,7 +6773,7 @@ async function loadSettingsPanel(){
     const apiRedactCb=$('settingsApiRedact');
     if(apiRedactCb){apiRedactCb.checked=settings.api_redact_enabled!==false;apiRedactCb.addEventListener('change',_schedulePreferencesAutosave,{once:false});}
     const showCliCb=$('settingsShowCliSessions');
-    if(showCliCb){showCliCb.checked=!!settings.show_cli_sessions;showCliCb.addEventListener('change',_schedulePreferencesAutosave,{once:false});}
+    if(showCliCb){showCliCb.checked=settings.show_cli_sessions!==false;showCliCb.addEventListener('change',_schedulePreferencesAutosave,{once:false});}
     const showCronCb=$('settingsShowCronSessions');
     if(showCronCb){
       showCronCb.checked=!!settings.show_cron_sessions;
diff --git a/tests/test_issue3988_show_cli_sessions_default.py b/tests/test_issue3988_show_cli_sessions_default.py
new file mode 100644
index 00000000..7909202e
--- /dev/null
+++ b/tests/test_issue3988_show_cli_sessions_default.py
@@ -0,0 +1,175 @@
+"""show_cli_sessions default-True + grandfather migration + hydration consistency (#3988).
+
+The default for ``show_cli_sessions`` flipped to **True** so that NEW installs
+surface CLI / TUI / Telegram / Discord / Hermes One sessions in the WebUI sidebar
+without users having to discover the toggle in Settings (the surprise described in
+#3988).
+
+Two correctness properties this pins:
+
+1. **Grandfather established installs OFF.** An existing user who already completed
+   onboarding and never opted in must NOT have their sidebar silently change. The
+   ``load_settings()`` backfill pins ``show_cli_sessions=False`` when the saved
+   settings predate the flip (``onboarding_completed`` True, key absent). Fresh
+   installs (no settings file / onboarding not completed) get the True default.
+
+2. **Default-true hydration at EVERY read site.** config.py, boot.js, and the
+   panels.js Settings checkbox must all default an *absent* value to True — a
+   ``!!value`` coerce would default the True setting OFF for a user with no saved
+   value (the #4006 default-mismatch class), showing config-ON-but-UI-OFF.
+
+Combines + supersedes the approaches in #3997 (rodboev) and #4222 (Sanjays2402).
+"""
+
+import json
+import pathlib
+
+import pytest
+
+import api.config as config
+
+ROOT = pathlib.Path(__file__).resolve().parent.parent
+
+
+def _read(rel):
+    return (ROOT / rel).read_text(encoding="utf-8")
+
+
+# ── 1. config.py default ──────────────────────────────────────────────────
+
+def test_show_cli_sessions_default_is_true_in_config():
+    assert config._SETTINGS_DEFAULTS.get("show_cli_sessions") is True, (
+        "show_cli_sessions must default to True so CLI/TUI/messaging sessions are "
+        "visible by default for new installs (#3988)"
+    )
+
+
+def test_show_cli_sessions_in_bool_keys():
+    assert "show_cli_sessions" in config._SETTINGS_BOOL_KEYS, (
+        "show_cli_sessions must be in _SETTINGS_BOOL_KEYS so it round-trips as a bool"
+    )
+
+
+# ── 2. Grandfather migration in load_settings() ───────────────────────────
+
+@pytest.fixture()
+def settings_file(tmp_path, monkeypatch):
+    """Point config.SETTINGS_FILE at a temp file for isolated load_settings tests."""
+    f = tmp_path / "settings.json"
+    monkeypatch.setattr(config, "SETTINGS_FILE", f)
+    return f
+
+
+def _write(f, data):
+    f.write_text(json.dumps(data), encoding="utf-8")
+
+
+def test_fresh_install_no_settings_file_defaults_on(settings_file):
+    """No settings file at all (brand-new install) → True (the new default)."""
+    assert not settings_file.exists()
+    loaded = config.load_settings()
+    assert loaded["show_cli_sessions"] is True
+
+
+def test_fresh_install_onboarding_not_completed_defaults_on(settings_file):
+    """Settings file with ONLY a not-yet-completed onboarding flag (still
+    mid-first-run, no other user state) → True."""
+    _write(settings_file, {"onboarding_completed": False})
+    loaded = config.load_settings()
+    assert loaded["show_cli_sessions"] is True
+
+
+def test_established_cli_user_without_onboarding_flag_grandfathered_off(settings_file):
+    """A CLI-configured user who tweaked a WebUI setting (e.g. theme) but never
+    ran the onboarding wizard is still an ESTABLISHED install — grandfather OFF.
+
+    Keying the grandfather only on onboarding_completed would miss this user and
+    silently flip their sidebar on (Opus #4230 review finding). Any persisted
+    setting other than a falsy onboarding flag marks the install established.
+    """
+    _write(settings_file, {"onboarding_completed": False, "theme": "dark"})
+    loaded = config.load_settings()
+    assert loaded["show_cli_sessions"] is False, (
+        "an install with persisted user settings (even without onboarding "
+        "completed) must be grandfathered OFF, not flipped on"
+    )
+
+
+def test_established_install_absent_key_grandfathered_off(settings_file):
+    """Established install (onboarding done) that never set the key → stays OFF.
+
+    This is the core grandfather guarantee: an existing user's sidebar must not
+    silently start showing CLI/messaging sessions after the default flips.
+    """
+    _write(settings_file, {"onboarding_completed": True, "theme": "dark"})
+    loaded = config.load_settings()
+    assert loaded["show_cli_sessions"] is False, (
+        "an onboarding-completed install with no saved show_cli_sessions must be "
+        "grandfathered OFF, not flipped on by the new default"
+    )
+
+
+def test_explicit_true_is_respected(settings_file):
+    """A user who explicitly opted in keeps it ON."""
+    _write(settings_file, {"onboarding_completed": True, "show_cli_sessions": True})
+    loaded = config.load_settings()
+    assert loaded["show_cli_sessions"] is True
+
+
+def test_explicit_false_is_respected(settings_file):
+    """A user who explicitly turned it off keeps it OFF."""
+    _write(settings_file, {"onboarding_completed": True, "show_cli_sessions": False})
+    loaded = config.load_settings()
+    assert loaded["show_cli_sessions"] is False
+
+
+def test_established_install_persists_grandfather_through_save(settings_file):
+    """save_settings() does load_settings() first, so the grandfathered False is
+    carried into the persisted blob — no window where a save flips an established
+    user ON. (save_settings writes the full merged dict.)"""
+    _write(settings_file, {"onboarding_completed": True})
+    # A save that doesn't mention show_cli_sessions must not flip it on.
+    config.save_settings({"theme": "light"})
+    persisted = json.loads(settings_file.read_text(encoding="utf-8"))
+    assert persisted.get("show_cli_sessions") is False, (
+        "save_settings must preserve the grandfathered OFF state for established "
+        "installs, never silently flip it on"
+    )
+
+
+# ── 3. Default-true hydration at every frontend read site ──────────────────
+#    (string-pins; guard against the #4006 !!-coerce default-mismatch class)
+
+def test_boot_hydration_defaults_true_when_setting_absent():
+    src = _read("static/boot.js")
+    assert "window._showCliSessions=s.show_cli_sessions!==false" in src, (
+        "boot.js must default _showCliSessions True when the saved value is absent"
+    )
+    assert "window._showCliSessions=!!s.show_cli_sessions" not in src, (
+        "boot.js must not use !!s.show_cli_sessions — that defaults the True "
+        "setting OFF for users with no saved value (#4006 mismatch class)"
+    )
+
+
+def test_boot_settings_load_failure_fallback_defaults_true():
+    """The settings-load-FAILED catch block must also default _showCliSessions
+    True, mirroring the config default — otherwise a transient settings-read
+    error silently hides CLI sessions (the #4006 catch-block-fallback class the
+    autoScrollFollow fix pinned)."""
+    src = _read("static/boot.js")
+    assert "window._showCliSessions=false" not in src, (
+        "the settings-load-failure fallback must not hardcode _showCliSessions "
+        "false — it should mirror the True default"
+    )
+
+
+def test_settings_checkbox_renders_checked_by_default():
+    src = _read("static/panels.js")
+    assert "showCliCb.checked=settings.show_cli_sessions!==false" in src, (
+        "the show-CLI-sessions checkbox must default checked (!== false), matching "
+        "the True config default"
+    )
+    assert "showCliCb.checked=!!settings.show_cli_sessions" not in src, (
+        "panels.js must not use !!settings.show_cli_sessions for the checkbox — "
+        "that renders it unchecked by default, contradicting the config default"
+    )
diff --git a/tests/test_workspace_symlink_delete_rename.py b/tests/test_workspace_symlink_delete_rename.py
new file mode 100644
index 00000000..ba1d294f
--- /dev/null
+++ b/tests/test_workspace_symlink_delete_rename.py
@@ -0,0 +1,252 @@
+"""Regression tests for #4217 — symlink guards on /api/file/delete and /api/file/rename."""
+import os
+
+import pytest
+
+import api.routes as routes
+
+
+@pytest.fixture()
+def workspace(tmp_path):
+    """Yield a real temporary workspace directory and clean up after."""
+    ws = tmp_path / "ws"
+    ws.mkdir()
+    yield ws
+
+
+class _FakeHandler:
+    pass
+
+
+def _patch_routes(ws):
+    """Monkey-patch routes helpers so handlers run without an HTTP server."""
+
+    class _S:
+        workspace = str(ws)
+
+    cap = {}
+    orig_j = routes.j
+    orig_bad = routes.bad
+    orig_get = routes.get_session_for_file_ops
+    routes.j = lambda h, o: (cap.__setitem__("ok", o), True)[1]
+    routes.bad = lambda h, m, c=400: (cap.__setitem__("bad", (m, c)), True)[1]
+    routes.get_session_for_file_ops = lambda sid: _S()
+    return cap, (orig_j, orig_bad, orig_get)
+
+
+def _restore_routes(originals):
+    routes.j, routes.bad, routes.get_session_for_file_ops = originals
+
+
+# ── DELETE symlink guards ────────────────────────────────────────────────
+
+def test_delete_workspace_symlink_to_dir_rejected(workspace):
+    real_dir = workspace / "real_dir"
+    real_dir.mkdir()
+    link = workspace / "link_to_dir"
+    try:
+        os.symlink(str(real_dir), str(link))
+    except (OSError, NotImplementedError):
+        pytest.skip("platform does not support symlinks")
+
+    cap, orig = _patch_routes(workspace)
+    try:
+        routes._handle_file_delete(
+            _FakeHandler(),
+            {"session_id": "x", "path": "link_to_dir", "recursive": True},
+        )
+    finally:
+        _restore_routes(orig)
+
+    assert "bad" in cap, f"expected 400, got {cap}"
+    assert cap["bad"][1] == 400
+    assert "Cannot delete a symlinked entry" in cap["bad"][0]
+    assert real_dir.exists(), "real target directory was deleted through the symlink"
+
+
+def test_delete_workspace_symlink_to_file_rejected(workspace):
+    real_file = workspace / "real_file.txt"
+    real_file.write_text("important")
+    link = workspace / "link_to_file.txt"
+    try:
+        os.symlink(str(real_file), str(link))
+    except (OSError, NotImplementedError):
+        pytest.skip("platform does not support symlinks")
+
+    cap, orig = _patch_routes(workspace)
+    try:
+        routes._handle_file_delete(
+            _FakeHandler(),
+            {"session_id": "x", "path": "link_to_file.txt"},
+        )
+    finally:
+        _restore_routes(orig)
+
+    assert "bad" in cap, f"expected 400, got {cap}"
+    assert cap["bad"][1] == 400
+    assert "Cannot delete a symlinked entry" in cap["bad"][0]
+    assert real_file.exists(), "real target file was deleted through the symlink"
+
+
+# ── RENAME symlink guards ───────────────────────────────────────────────
+
+def test_rename_workspace_symlink_to_dir_rejected(workspace):
+    real_dir = workspace / "real_dir"
+    real_dir.mkdir()
+    link = workspace / "link_to_dir"
+    try:
+        os.symlink(str(real_dir), str(link))
+    except (OSError, NotImplementedError):
+        pytest.skip("platform does not support symlinks")
+
+    cap, orig = _patch_routes(workspace)
+    try:
+        routes._handle_file_rename(
+            _FakeHandler(),
+            {"session_id": "x", "path": "link_to_dir", "new_name": "renamed"},
+        )
+    finally:
+        _restore_routes(orig)
+
+    assert "bad" in cap, f"expected 400, got {cap}"
+    assert cap["bad"][1] == 400
+    assert "Cannot rename a symlinked entry" in cap["bad"][0]
+
+
+def test_rename_workspace_symlink_to_file_rejected(workspace):
+    real_file = workspace / "real_file.txt"
+    real_file.write_text("important")
+    link = workspace / "link_to_file.txt"
+    try:
+        os.symlink(str(real_file), str(link))
+    except (OSError, NotImplementedError):
+        pytest.skip("platform does not support symlinks")
+
+    cap, orig = _patch_routes(workspace)
+    try:
+        routes._handle_file_rename(
+            _FakeHandler(),
+            {"session_id": "x", "path": "link_to_file.txt", "new_name": "renamed.txt"},
+        )
+    finally:
+        _restore_routes(orig)
+
+    assert "bad" in cap, f"expected 400, got {cap}"
+    assert cap["bad"][1] == 400
+    assert "Cannot rename a symlinked entry" in cap["bad"][0]
+
+
+# ── Non-symlink operations still work ───────────────────────────────────
+
+def test_delete_real_dir_still_works(workspace):
+    real_dir = workspace / "deleteme"
+    real_dir.mkdir()
+    (real_dir / "child.txt").write_text("x")
+
+    cap, orig = _patch_routes(workspace)
+    try:
+        routes._handle_file_delete(
+            _FakeHandler(),
+            {"session_id": "x", "path": "deleteme", "recursive": True},
+        )
+    finally:
+        _restore_routes(orig)
+
+    assert "ok" in cap, f"expected success, got {cap}"
+    assert cap["ok"]["ok"] is True
+    assert not real_dir.exists()
+
+
+def test_rename_real_file_still_works(workspace):
+    real_file = workspace / "old_name.txt"
+    real_file.write_text("content")
+
+    cap, orig = _patch_routes(workspace)
+    try:
+        routes._handle_file_rename(
+            _FakeHandler(),
+            {"session_id": "x", "path": "old_name.txt", "new_name": "new_name.txt"},
+        )
+    finally:
+        _restore_routes(orig)
+
+    assert "ok" in cap, f"expected success, got {cap}"
+    assert cap["ok"]["ok"] is True
+    assert not real_file.exists()
+    assert (workspace / "new_name.txt").exists()
+
+
+# ── Existing move guard pinned ──────────────────────────────────────────
+
+def test_move_workspace_symlink_still_rejected(workspace):
+    real_file = workspace / "real.txt"
+    real_file.write_text("data")
+    dest = workspace / "dest"
+    dest.mkdir()
+    link = workspace / "link.txt"
+    try:
+        os.symlink(str(real_file), str(link))
+    except (OSError, NotImplementedError):
+        pytest.skip("platform does not support symlinks")
+
+    cap, orig = _patch_routes(workspace)
+    try:
+        routes._handle_file_move(
+            _FakeHandler(),
+            {"session_id": "x", "path": "link.txt", "dest_dir": "dest"},
+        )
+    finally:
+        _restore_routes(orig)
+
+    assert "bad" in cap, f"expected 400, got {cap}"
+    assert cap["bad"][1] == 400
+    assert "Cannot move a symlinked entry" in cap["bad"][0]
+
+
+# ── Dangling symlinks: guard must fire BEFORE the exists() 404 (#4230 review) ──
+
+def test_delete_dangling_symlink_rejected_not_404(workspace):
+    """A dangling workspace symlink (target removed) must be rejected by the
+    symlink guard (400), not misclassified as 404 'File not found' and left
+    permanently undeletable. The is_symlink() check must precede exists()."""
+    link = workspace / "dangling_del"
+    try:
+        os.symlink(str(workspace / "gone_target"), str(link))
+    except (OSError, NotImplementedError):
+        pytest.skip("platform does not support symlinks")
+
+    cap, orig = _patch_routes(workspace)
+    try:
+        routes._handle_file_delete(
+            _FakeHandler(),
+            {"session_id": "x", "path": "dangling_del", "recursive": True},
+        )
+    finally:
+        _restore_routes(orig)
+
+    assert "bad" in cap, f"expected 400, got {cap}"
+    assert cap["bad"][1] == 400
+    assert "Cannot delete a symlinked entry" in cap["bad"][0]
+
+
+def test_rename_dangling_symlink_rejected_not_404(workspace):
+    """A dangling workspace symlink must be rejected by the rename guard (400),
+    not 404'd before the guard fires."""
+    link = workspace / "dangling_ren"
+    try:
+        os.symlink(str(workspace / "gone_target"), str(link))
+    except (OSError, NotImplementedError):
+        pytest.skip("platform does not support symlinks")
+
+    cap, orig = _patch_routes(workspace)
+    try:
+        routes._handle_file_rename(
+            _FakeHandler(),
+            {"session_id": "x", "path": "dangling_ren", "new_name": "renamed"},
+        )
+    finally:
+        _restore_routes(orig)
+
+    assert "bad" in cap, f"expected 400, got {cap}"
+    assert cap["bad"][1] == 400
+    assert "Cannot rename a symlinked entry" in cap["bad"][0]