diff --git a/hermes_cli/main.py b/hermes_cli/main.py
index 318e55d3efe..a178daf581e 100644
--- a/hermes_cli/main.py
+++ b/hermes_cli/main.py
@@ -1146,7 +1146,7 @@ def _make_tui_argv(tui_dir: Path, tui_dev: bool) -> tuple[list[str], Path]:
             p = Path(ext_dir)
             if (p / "dist" / "entry.js").is_file():
                 node = _node_bin("node")
-                return [node, str(p / "dist" / "entry.js")], p
+                return [node, "--expose-gc", str(p / "dist" / "entry.js")], p
 
         # 1b. Bundled in wheel (pip install)
         bundled = _find_bundled_tui()
@@ -1229,7 +1229,7 @@ def _make_tui_argv(tui_dir: Path, tui_dev: bool) -> tuple[list[str], Path]:
             sys.exit(1)
 
     node = _node_bin("node")
-    return [node, str(tui_dir / "dist" / "entry.js")], tui_dir
+    return [node, "--expose-gc", str(tui_dir / "dist" / "entry.js")], tui_dir
 
 
 def _normalize_tui_toolsets(toolsets: object) -> list[str]:
@@ -1351,16 +1351,16 @@ def _launch_tui(
         env["HERMES_TUI_TOOL_PROGRESS"] = "off"
     if accept_hooks:
         env["HERMES_ACCEPT_HOOKS"] = "1"
-    # Guarantee an 8GB V8 heap + exposed GC for the TUI. Default node cap is
-    # ~1.5–4GB depending on version and can fatal-OOM on long sessions with
-    # large transcripts / reasoning blobs. Token-level merge: respect any
-    # user-supplied --max-old-space-size (they may have set it higher) and
-    # avoid duplicating --expose-gc.
+    # Guarantee an 8GB V8 heap for the TUI. Default node cap is ~1.5–4GB
+    # depending on version and can fatal-OOM on long sessions with large
+    # transcripts / reasoning blobs. Token-level merge: respect any
+    # user-supplied --max-old-space-size (they may have set it higher).
+    # --expose-gc is *not* added here: Node rejects it in NODE_OPTIONS
+    # ("--expose-gc is not allowed in NODE_OPTIONS") and refuses to start.
+    # It is passed as a direct argv flag in _make_tui_argv() instead.
     _tokens = env.get("NODE_OPTIONS", "").split()
     if not any(t.startswith("--max-old-space-size=") for t in _tokens):
         _tokens.append("--max-old-space-size=8192")
-    if "--expose-gc" not in _tokens:
-        _tokens.append("--expose-gc")
     env["NODE_OPTIONS"] = " ".join(_tokens)
     # HERMES_TUI_RESUME is an internal hand-off from the Python wrapper to the
     # Ink app.  Because we start from os.environ.copy(), an exported/stale value