fix(webui): isolate folder picker environment

docs/webui.md

@@ -133,7 +133,8 @@ or a result you must retain.
 
 Use the workspace picker before starting project-specific work. This gives the
 agent the right project context for file paths, shell commands, and session
-metadata.
+metadata. A locally hosted WebUI opens the operating system's folder chooser
+when one is available; remote deployments keep the manual absolute path entry.
 
 Selecting a project does not replace the configured agent workspace. The two
 paths have different responsibilities:

nanobot/webui/native_folder_picker.py

@@ -11,6 +11,48 @@ from dataclasses import dataclass
 from pathlib import Path
 
 _PICKER_TIMEOUT_SECONDS = 300
+_COMMON_ENV_KEYS = (
+    "HOME",
+    "LANG",
+    "LANGUAGE",
+    "LC_ALL",
+    "LC_CTYPE",
+    "LC_MESSAGES",
+    "LOGNAME",
+    "PATH",
+    "SHELL",
+    "TMPDIR",
+    "USER",
+)
+_LINUX_GUI_ENV_KEYS = (
+    "DBUS_SESSION_BUS_ADDRESS",
+    "DESKTOP_SESSION",
+    "DISPLAY",
+    "WAYLAND_DISPLAY",
+    "XAUTHORITY",
+    "XDG_CURRENT_DESKTOP",
+    "XDG_RUNTIME_DIR",
+)
+_MACOS_GUI_ENV_KEYS = ("SECURITYSESSIONID", "__CF_USER_TEXT_ENCODING")
+_WINDOWS_GUI_ENV_KEYS = (
+    "APPDATA",
+    "COMSPEC",
+    "HOMEDRIVE",
+    "HOMEPATH",
+    "LOCALAPPDATA",
+    "PATHEXT",
+    "ProgramData",
+    "ProgramFiles",
+    "ProgramFiles(x86)",
+    "ProgramW6432",
+    "SESSIONNAME",
+    "SYSTEMROOT",
+    "TEMP",
+    "TMP",
+    "USERDOMAIN",
+    "USERNAME",
+    "USERPROFILE",
+)
 
 
 class NativeFolderPickerError(RuntimeError):
@@ -94,6 +136,22 @@ def native_folder_picker_available() -> bool:
     return _picker_command() is not None
 
 
+def _picker_environment() -> dict[str, str]:
+    """Pass only host UI/runtime variables, never provider or gateway secrets."""
+    keys: list[str] = list(_COMMON_ENV_KEYS)
+    if sys.platform == "darwin":
+        keys.extend(_MACOS_GUI_ENV_KEYS)
+    elif sys.platform == "win32":
+        keys.extend(_WINDOWS_GUI_ENV_KEYS)
+    elif sys.platform.startswith("linux"):
+        keys.extend(_LINUX_GUI_ENV_KEYS)
+    return {
+        key: value
+        for key in keys
+        if (value := os.environ.get(key)) is not None
+    }
+
+
 async def _stop_process(process: asyncio.subprocess.Process) -> None:
     if process.returncode is not None:
         return
@@ -113,11 +171,15 @@ async def pick_native_folder() -> str | None:
     if command is None:
         raise NativeFolderPickerError("native folder picker is unavailable on this host")
 
+    try:
         process = await asyncio.create_subprocess_exec(
             *command.argv,
+            env=_picker_environment(),
             stdout=asyncio.subprocess.PIPE,
             stderr=asyncio.subprocess.PIPE,
         )
+    except OSError as exc:
+        raise NativeFolderPickerError("native folder picker failed to start") from exc
     try:
         stdout, stderr = await asyncio.wait_for(
             process.communicate(),

tests/utils/test_native_folder_picker.py

@@ -28,6 +28,41 @@ async def test_pick_native_folder_returns_selected_directory(tmp_path, monkeypat
     assert await picker.pick_native_folder() == str(selected)
 
 
+@pytest.mark.asyncio
+async def test_pick_native_folder_uses_secret_free_environment(tmp_path, monkeypatch) -> None:
+    selected = tmp_path / "project"
+    selected.mkdir()
+    command = _picker_command(tmp_path, f"print({str(selected)!r}, end='')")
+    monkeypatch.setattr(picker, "_picker_command", lambda: command)
+    monkeypatch.setenv("HOME", str(tmp_path))
+    monkeypatch.setenv("OPENAI_API_KEY", "must-not-reach-picker")
+    original_spawn = picker.asyncio.create_subprocess_exec
+    captured_env: dict[str, str] = {}
+
+    async def capture_spawn(*args, **kwargs):
+        captured_env.update(kwargs["env"])
+        return await original_spawn(*args, **kwargs)
+
+    monkeypatch.setattr(picker.asyncio, "create_subprocess_exec", capture_spawn)
+
+    assert await picker.pick_native_folder() == str(selected)
+    assert captured_env["HOME"] == str(tmp_path)
+    assert "OPENAI_API_KEY" not in captured_env
+
+
+def test_picker_environment_preserves_linux_display_context(monkeypatch) -> None:
+    monkeypatch.setattr(picker.sys, "platform", "linux")
+    monkeypatch.setenv("DISPLAY", ":42")
+    monkeypatch.setenv("DBUS_SESSION_BUS_ADDRESS", "unix:path=/run/user/test/bus")
+    monkeypatch.setenv("ANTHROPIC_API_KEY", "must-not-reach-picker")
+
+    environment = picker._picker_environment()
+
+    assert environment["DISPLAY"] == ":42"
+    assert environment["DBUS_SESSION_BUS_ADDRESS"] == "unix:path=/run/user/test/bus"
+    assert "ANTHROPIC_API_KEY" not in environment
+
+
 @pytest.mark.asyncio
 async def test_pick_native_folder_maps_dialog_cancel_to_none(tmp_path, monkeypatch) -> None:
     command = _picker_command(tmp_path, "raise SystemExit(1)")
@@ -61,3 +96,17 @@ async def test_pick_native_folder_reports_unavailable(monkeypatch) -> None:
     assert picker.native_folder_picker_available() is False
     with pytest.raises(picker.NativeFolderPickerError, match="unavailable"):
         await picker.pick_native_folder()
+
+
+@pytest.mark.asyncio
+async def test_pick_native_folder_wraps_process_start_failure(tmp_path, monkeypatch) -> None:
+    command = _picker_command(tmp_path, "raise AssertionError('not started')")
+    monkeypatch.setattr(picker, "_picker_command", lambda: command)
+
+    async def fail_spawn(*args, **kwargs):
+        raise OSError("executable disappeared")
+
+    monkeypatch.setattr(picker.asyncio, "create_subprocess_exec", fail_spawn)
+
+    with pytest.raises(picker.NativeFolderPickerError, match="failed to start"):
+        await picker.pick_native_folder()