fix(cli): foreground the WebUI browser

nanobot/cli/gateway_runtime.py

@@ -23,6 +23,7 @@ from nanobot.cli.webui_support import (
     _gateway_health_bind_note,
     _gateway_health_url,
     _host_for_local_browser,
+    _launch_browser,
     _prepare_webui_bundle_for_gateway,
     _print_foreground_port_conflict,
     _tcp_endpoint_reachable,
@@ -864,7 +865,6 @@ def _run_gateway(
         """Wait for the gateway to bind, then point the user's browser at the webui."""
         if not open_browser_url:
             return
-        import webbrowser
         from urllib.parse import urlparse
 
         # Channels start asynchronously. When the caller supplies a backend
@@ -896,8 +896,10 @@ def _run_gateway(
                 await asyncio.sleep(0.1)
         display_url = _webui_display_url(open_browser_url)
         try:
-            webbrowser.open(open_browser_url)
+            if _launch_browser(open_browser_url):
                 console.print(f"[green]✓[/green] Opened browser at {display_url}")
+            else:
+                console.print(f"[yellow]Could not open browser; visit {display_url}[/yellow]")
         except Exception as e:
             console.print(f"[yellow]Could not open browser ({e}); visit {display_url}[/yellow]")
 

nanobot/cli/webui_support.py

@@ -1,7 +1,9 @@
 """Shared WebUI setup, URL, health, and browser helpers."""
 
+import subprocess
 import sys
 import time
+import webbrowser
 from collections.abc import Callable
 from pathlib import Path
 from typing import TYPE_CHECKING, Any
@@ -40,6 +42,7 @@ __all__ = [
     "_gateway_instance_command",
     "_host_for_local_browser",
     "_load_webui_setup_config",
+    "_launch_browser",
     "_open_webui_browser",
     "_prepare_webui_bundle_for_gateway",
     "_print_foreground_port_conflict",
@@ -60,6 +63,20 @@ __all__ = [
 console = Console()
 
 
+def _launch_browser(url: str) -> bool:
+    """Open *url* and request a foreground browser window."""
+    if sys.platform == "darwin":
+        result = subprocess.run(
+            ["open", url],
+            stdin=subprocess.DEVNULL,
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+            check=False,
+        )
+        return result.returncode == 0
+    return bool(webbrowser.open(url, new=2, autoraise=True))
+
+
 def _confirm_webui_action(message: str, *, yes: bool) -> None:
     """Confirm a WebUI first-run mutation or fail clearly in non-interactive shells."""
     if yes:
@@ -419,14 +436,14 @@ def _print_foreground_port_conflict(
 
 def _open_webui_browser(url: str, *, wait: bool = True) -> None:
     """Open the WebUI in the user's default browser, with a copyable fallback."""
-    import webbrowser
-
     if wait:
         _wait_for_webui(url)
     display_url = _webui_display_url(url)
     try:
-        webbrowser.open(url)
+        if _launch_browser(url):
             console.print(f"[green]✓[/green] Opened WebUI: [cyan]{display_url}[/cyan]")
+        else:
+            console.print(f"[yellow]Could not open browser; visit {display_url}[/yellow]")
     except Exception as exc:
         console.print(f"[yellow]Could not open browser ({exc}); visit {display_url}[/yellow]")
 

tests/cli/test_commands.py

@@ -2534,7 +2534,11 @@ def test_webui_yes_still_refuses_invalid_custom_model_setup(
 def test_open_webui_browser_redacts_bootstrap_secret(monkeypatch, capsys) -> None:
     opened: list[str] = []
     url = "http://127.0.0.1:8765/#/?bootstrapSecret=super-secret"
-    monkeypatch.setattr("webbrowser.open", lambda value: opened.append(value))
+    monkeypatch.setattr(
+        cli_webui_support,
+        "_launch_browser",
+        lambda value: opened.append(value) or True,
+    )
 
     cli_webui_support._open_webui_browser(url, wait=False)
 
@@ -2544,6 +2548,42 @@ def test_open_webui_browser_redacts_bootstrap_secret(monkeypatch, capsys) -> Non
     assert "super-secret" not in output
 
 
+def test_open_webui_browser_reports_launch_failure(monkeypatch, capsys) -> None:
+    monkeypatch.setattr(cli_webui_support, "_launch_browser", lambda _value: False)
+
+    cli_webui_support._open_webui_browser("http://127.0.0.1:8765/", wait=False)
+
+    assert "Could not open browser; visit http://127.0.0.1:8765/" in _strip_ansi(
+        capsys.readouterr().out
+    )
+
+
+def test_launch_browser_uses_macos_foreground_opener(monkeypatch) -> None:
+    seen: list[list[str]] = []
+    monkeypatch.setattr(cli_webui_support.sys, "platform", "darwin")
+    monkeypatch.setattr(
+        cli_webui_support.subprocess,
+        "run",
+        lambda command, **_kwargs: seen.append(command) or SimpleNamespace(returncode=0),
+    )
+
+    assert cli_webui_support._launch_browser("http://127.0.0.1:8765/") is True
+    assert seen == [["open", "http://127.0.0.1:8765/"]]
+
+
+def test_launch_browser_uses_default_browser_off_macos(monkeypatch) -> None:
+    opened: list[tuple[str, int, bool]] = []
+    monkeypatch.setattr(cli_webui_support.sys, "platform", "linux")
+    monkeypatch.setattr(
+        cli_webui_support.webbrowser,
+        "open",
+        lambda url, *, new, autoraise: opened.append((url, new, autoraise)) or True,
+    )
+
+    assert cli_webui_support._launch_browser("http://127.0.0.1:8765/") is True
+    assert opened == [("http://127.0.0.1:8765/", 2, True)]
+
+
 def test_webui_foreground_attaches_to_existing_managed_gateway(monkeypatch, tmp_path: Path) -> None:
     config_file = tmp_path / "config.json"
     config_file.write_text("{}")