tui: make theme configurable via CLI settings

openhands_cli/stores/__init__.py

@@ -5,6 +5,7 @@
 )
 from openhands_cli.stores.cli_settings import (
     DEFAULT_MAX_REFINEMENT_ITERATIONS,
+    VALID_THEMES,
     CliSettings,
     CriticSettings,
 )
@@ -16,5 +17,6 @@
     "CriticSettings",
     "DEFAULT_MAX_REFINEMENT_ITERATIONS",
     "MissingEnvironmentVariablesError",
+    "VALID_THEMES",
     "check_and_warn_env_vars",
 ]

openhands_cli/stores/cli_settings.py

@@ -5,6 +5,7 @@
 from pathlib import Path
 
 from pydantic import BaseModel, field_validator
+from textual.theme import BUILTIN_THEMES
 
 
 # Refinement triggers when predicted success probability falls below this threshold
@@ -46,13 +47,27 @@ def validate_max_iterations(cls, v: int) -> int:
         return v
 
 
+VALID_THEMES: set[str] = {"openhands"} | set(BUILTIN_THEMES.keys())
+
+
 class CliSettings(BaseModel):
     """Model for CLI-level settings."""
 
     default_cells_expanded: bool = False
     auto_open_plan_panel: bool = True
+    theme: str = "openhands"
     critic: CriticSettings = CriticSettings()
 
+    @field_validator("theme")
+    @classmethod
+    def validate_theme(cls, v: str) -> str:
+        """Validate that theme is a known Textual built-in or 'openhands'."""
+        if v not in VALID_THEMES:
+            raise ValueError(
+                f"Unknown theme '{v}'. Must be one of: {sorted(VALID_THEMES)}"
+            )
+        return v
+
     @classmethod
     def get_config_path(cls) -> Path:
         """Get the path to the CLI configuration file."""

openhands_cli/tui/modals/settings/components/cli_settings_tab.py

@@ -4,9 +4,9 @@
 
 from textual.app import ComposeResult
 from textual.containers import Container, Horizontal, VerticalScroll
-from textual.widgets import Label, Static, Switch
+from textual.widgets import Label, Select, Static, Switch
 
-from openhands_cli.stores.cli_settings import CliSettings
+from openhands_cli.stores.cli_settings import VALID_THEMES, CliSettings
 
 
 class SettingsSwitch(Container):
@@ -57,6 +57,8 @@ def __init__(self, initial_settings: CliSettings | None = None, **kwargs):
 
     def compose(self) -> ComposeResult:
         """Compose the CLI settings tab content."""
+        theme_options = [(name, name) for name in sorted(VALID_THEMES)]
+
         with VerticalScroll(id="cli_settings_content"):
             yield Static("CLI Settings", classes="form_section_title")
 
@@ -82,11 +84,28 @@ def compose(self) -> ComposeResult:
                 value=self._initial_settings.auto_open_plan_panel,
             )
 
+            with Container(classes="form_group"):
+                yield Label("Theme:", classes="form_label")
+                yield Select(
+                    theme_options,
+                    value=self._initial_settings.theme,
+                    id="theme_select",
+                    classes="form_select",
+                    type_to_search=True,
+                )
+                yield Static(
+                    "Choose the TUI color theme. The custom 'openhands' theme "
+                    "is the default. Textual built-in themes like 'dracula', "
+                    "'nord', 'catppuccin-mocha', etc. are also available.",
+                    classes="form_help",
+                )
+
     def get_updated_fields(self) -> dict[str, Any]:
         """Return only the fields this tab manages.
 
         Returns:
-            Dict with 'default_cells_expanded' and 'auto_open_plan_panel' values.
+            Dict with 'default_cells_expanded', 'auto_open_plan_panel', and
+            'theme' values.
         """
         return {
             "default_cells_expanded": self.query_one(
@@ -95,4 +114,5 @@ def get_updated_fields(self) -> dict[str, Any]:
             "auto_open_plan_panel": self.query_one(
                 "#auto_open_plan_panel_switch", Switch
             ).value,
+            "theme": self.query_one("#theme_select", Select).value,
         }

openhands_cli/tui/textual_app.py

@@ -209,11 +209,11 @@ def __init__(
 
         self.plan_panel: PlanSidePanel = PlanSidePanel(self)
 
-        # Register the custom theme
+        # Register the custom theme (always available as an option)
         self.register_theme(OPENHANDS_THEME)
 
-        # Set the theme as active
-        self.theme = "openhands"
+        # Set the active theme from CLI settings
+        self.theme = cli_settings.theme
 
     CSS_PATH = "textual_app.tcss"
 

tests/tui/modals/settings/test_cli_settings.py

@@ -7,6 +7,7 @@
 from pydantic import ValidationError
 
 from openhands_cli.stores import CliSettings, CriticSettings
+from openhands_cli.stores.cli_settings import VALID_THEMES
 
 
 class TestCriticSettingsValidation:
@@ -89,6 +90,7 @@ def test_defaults(self):
         cfg = CliSettings()
         assert cfg.default_cells_expanded is False
         assert cfg.auto_open_plan_panel is True
+        assert cfg.theme == "openhands"
         assert cfg.critic.enable_critic is True
         assert cfg.critic.enable_iterative_refinement is False
         assert cfg.critic.critic_threshold == 0.6
@@ -100,6 +102,31 @@ def test_default_cells_expanded_accepts_bool(self, value: bool):
         cfg = CliSettings(default_cells_expanded=value)
         assert cfg.default_cells_expanded is value
 
+    @pytest.mark.parametrize("theme", ["openhands", "dracula", "nord", "tokyo-night"])
+    def test_theme_accepts_valid_values(self, theme: str):
+        cfg = CliSettings(theme=theme)
+        assert cfg.theme == theme
+
+    def test_theme_rejects_unknown_value(self):
+        with pytest.raises(ValidationError) as exc_info:
+            CliSettings(theme="nonexistent-theme")
+        assert "Unknown theme" in str(exc_info.value)
+
+    def test_valid_themes_contains_openhands_and_builtins(self):
+        assert "openhands" in VALID_THEMES
+        assert "dracula" in VALID_THEMES
+        assert "nord" in VALID_THEMES
+
+    def test_theme_roundtrip(self, tmp_path: Path):
+        config_path = tmp_path / "cli_config.json"
+        cfg = CliSettings(theme="dracula")
+
+        with patch.object(CliSettings, "get_config_path", return_value=config_path):
+            cfg.save()
+            loaded = CliSettings.load()
+
+        assert loaded.theme == "dracula"
+
     @pytest.mark.parametrize(
         "env_value, expected",
         [
@@ -186,6 +213,7 @@ def test_save_writes_expected_json_format(self, tmp_path: Path):
         cfg = CliSettings(
             default_cells_expanded=False,
             auto_open_plan_panel=False,
+            theme="openhands",
             critic=CriticSettings(
                 enable_critic=False,
                 enable_iterative_refinement=False,
@@ -202,6 +230,7 @@ def test_save_writes_expected_json_format(self, tmp_path: Path):
             {
                 "default_cells_expanded": False,
                 "auto_open_plan_panel": False,
+                "theme": "openhands",
                 "critic": {
                     "enable_critic": False,
                     "enable_iterative_refinement": False,

tests/tui/modals/settings/test_cli_settings_tab.py

@@ -4,7 +4,7 @@
 
 import pytest
 from textual.app import App, ComposeResult
-from textual.widgets import Switch
+from textual.widgets import Select, Switch
 
 from openhands_cli.stores.cli_settings import CliSettings
 from openhands_cli.tui.modals.settings.components.cli_settings_tab import (
@@ -123,8 +123,45 @@ async def test_get_updated_fields_returns_only_managed_fields(self):
             tab = app.query_one(CliSettingsTab)
             result = tab.get_updated_fields()
 
-            # Should only contain the 2 fields this tab manages
+            # Should contain the 3 fields this tab manages
             assert set(result.keys()) == {
                 "default_cells_expanded",
                 "auto_open_plan_panel",
+                "theme",
             }
+
+    @pytest.mark.asyncio
+    async def test_compose_renders_theme_select_with_default(self):
+        """Verify the theme selector is rendered with the default value."""
+        app = _TestApp(initial_settings=CliSettings())
+
+        async with app.run_test():
+            tab = app.query_one(CliSettingsTab)
+            select = tab.query_one("#theme_select", Select)
+            assert select.value == "openhands"
+
+    @pytest.mark.asyncio
+    async def test_compose_renders_theme_select_with_custom_value(self):
+        """Verify the theme selector reflects a non-default initial value."""
+        initial = CliSettings(theme="dracula")
+        app = _TestApp(initial_settings=initial)
+
+        async with app.run_test():
+            tab = app.query_one(CliSettingsTab)
+            select = tab.query_one("#theme_select", Select)
+            assert select.value == "dracula"
+
+    @pytest.mark.asyncio
+    async def test_get_updated_fields_reflects_theme_change(self):
+        """Verify get_updated_fields() captures theme select state."""
+        initial = CliSettings(theme="openhands")
+        app = _TestApp(initial_settings=initial)
+
+        async with app.run_test():
+            tab = app.query_one(CliSettingsTab)
+            select = tab.query_one("#theme_select", Select)
+
+            select.value = "nord"
+
+            result = tab.get_updated_fields()
+            assert result["theme"] == "nord"