diff --git a/hermes_cli/browser_connect.py b/hermes_cli/browser_connect.py
index c3f2657d2b..25e4a5d91b 100644
--- a/hermes_cli/browser_connect.py
+++ b/hermes_cli/browser_connect.py
@@ -250,7 +250,14 @@ def _detect_default_darwin() -> str | None:
         ["defaults", "read", "com.apple.LaunchServices/com.apple.launchservices.secure", "LSHandlers"],
     ):
         try:
-            out = subprocess.run(reader, capture_output=True, text=True, timeout=5).stdout.lower()
+            out = subprocess.run(
+                reader,
+                capture_output=True,
+                text=True,
+                encoding="utf-8",
+                errors="replace",
+                timeout=5,
+            ).stdout.lower()
         except Exception:
             out = ""
         for frag, browser in _DARWIN_BUNDLE_MAP:
@@ -267,7 +274,11 @@ def _detect_default_linux() -> str | None:
     try:
         out = subprocess.run(
             ["xdg-settings", "get", "default-web-browser"],
-            capture_output=True, text=True, timeout=5,
+            capture_output=True,
+            text=True,
+            encoding="utf-8",
+            errors="replace",
+            timeout=5,
         ).stdout.strip().lower()
     except Exception:
         out = ""
diff --git a/tests/tools/test_browser_extension_router_wiring.py b/tests/tools/test_browser_extension_router_wiring.py
index bbdd4bf1be..8fb7e62869 100644
--- a/tests/tools/test_browser_extension_router_wiring.py
+++ b/tests/tools/test_browser_extension_router_wiring.py
@@ -36,7 +36,11 @@ def _route_spy(monkeypatch):
 
     monkeypatch.setattr(browser_tool, "routed_browser_handler", spy)
     monkeypatch.setattr(browser_cdp_tool, "routed_browser_handler", spy)
-    monkeypatch.setattr(browser_tool, "browser_navigate", lambda url="", task_id=None: "legacy-nav")
+    monkeypatch.setattr(
+        browser_tool,
+        "browser_navigate",
+        lambda url="", task_id=None, local_browser=False: "legacy-nav",
+    )
     monkeypatch.setattr(browser_cdp_tool, "browser_cdp", lambda *a, **k: "legacy-cdp")
     return calls
 
diff --git a/tests/tools/test_browser_open_timeout.py b/tests/tools/test_browser_open_timeout.py
index 6d791ee282..570f8f9b6a 100644
--- a/tests/tools/test_browser_open_timeout.py
+++ b/tests/tools/test_browser_open_timeout.py
@@ -96,7 +96,9 @@ class TestBrowserNavigateOpenTimeout:
         monkeypatch.setattr(bt, "_is_camofox_mode", lambda: False)
         monkeypatch.setattr(bt, "_is_local_backend", lambda: True)
         monkeypatch.setattr(bt, "_is_local_sidecar_key", lambda key: False)
-        monkeypatch.setattr(bt, "_navigation_session_key", lambda task_id, url: task_id)
+        monkeypatch.setattr(
+            bt, "_navigation_session_key", lambda task_id, url, local_browser=False: task_id
+        )
         monkeypatch.setattr(bt, "_maybe_start_recording", lambda *a, **kw: None)
         monkeypatch.setattr(bt, "check_website_access", lambda url: None)