feat(webui): add model settings runtime refresh

nanobot/agent/loop.py

@@ -18,6 +18,7 @@ from nanobot.agent.context import ContextBuilder
 from nanobot.agent.hook import AgentHook, AgentHookContext, CompositeHook
 from nanobot.agent.memory import Consolidator, Dream
 from nanobot.agent.runner import _MAX_INJECTIONS_PER_TURN, AgentRunner, AgentRunSpec
+from nanobot.agent.runtime import AgentRuntime
 from nanobot.agent.skills import BUILTIN_SKILLS_DIR
 from nanobot.agent.subagent import SubagentManager
 from nanobot.agent.tools.ask import (
@@ -194,6 +195,8 @@ class AgentLoop:
         unified_session: bool = False,
         disabled_skills: list[str] | None = None,
         tools_config: ToolsConfig | None = None,
+        runtime_loader: Callable[[], AgentRuntime] | None = None,
+        runtime_signature: tuple[object, ...] | None = None,
     ):
         from nanobot.config.schema import ExecToolConfig, ToolsConfig, WebToolsConfig
 
@@ -202,6 +205,8 @@ class AgentLoop:
         self.bus = bus
         self.channels_config = channels_config
         self.provider = provider
+        self._runtime_loader = runtime_loader
+        self._runtime_signature = runtime_signature
         self.workspace = workspace
         self.model = model or provider.get_default_model()
         self.max_iterations = (
@@ -288,6 +293,43 @@ class AgentLoop:
         self.commands = CommandRouter()
         register_builtin_commands(self.commands)
 
+    def _apply_runtime(self, runtime: AgentRuntime) -> None:
+        """Swap model/provider for future turns without disturbing an active one."""
+        provider = runtime.provider
+        model = runtime.model
+        context_window_tokens = runtime.context_window_tokens
+        if self.provider is provider and self.model == model:
+            return
+        old_model = self.model
+        self.provider = provider
+        self.model = model
+        self.context_window_tokens = context_window_tokens
+        self.runner.provider = provider
+        self.subagents.provider = provider
+        self.subagents.model = model
+        self.subagents.runner.provider = provider
+        self.consolidator.provider = provider
+        self.consolidator.model = model
+        self.consolidator.context_window_tokens = context_window_tokens
+        self.consolidator.max_completion_tokens = provider.generation.max_tokens
+        self.dream.provider = provider
+        self.dream.model = model
+        self.dream._runner.provider = provider
+        self._runtime_signature = runtime.signature
+        logger.info("Runtime model switched for next turn: {} -> {}", old_model, model)
+
+    def _refresh_runtime(self) -> None:
+        if self._runtime_loader is None:
+            return
+        try:
+            runtime = self._runtime_loader()
+        except Exception:
+            logger.exception("Failed to refresh runtime config")
+            return
+        if runtime.signature == self._runtime_signature:
+            return
+        self._apply_runtime(runtime)
+
     def _register_default_tools(self) -> None:
         """Register the default set of tools."""
         allowed_dir = (
@@ -766,6 +808,7 @@ class AgentLoop:
         pending_queue: asyncio.Queue | None = None,
     ) -> OutboundMessage | None:
         """Process a single inbound message and return the response."""
+        self._refresh_runtime()
         # System messages: parse origin from chat_id ("channel:chat_id")
         if msg.channel == "system":
             channel, chat_id = (

nanobot/agent/runtime.py

@@ -0,0 +1,112 @@
+"""Runtime model/provider resolution for agent turns."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from pathlib import Path
+
+from nanobot.config.schema import Config
+from nanobot.providers.base import GenerationSettings, LLMProvider
+from nanobot.providers.registry import find_by_name
+
+
+@dataclass(frozen=True)
+class AgentRuntime:
+    provider: LLMProvider
+    model: str
+    context_window_tokens: int
+    signature: tuple[object, ...]
+
+
+def make_provider(config: Config) -> LLMProvider:
+    """Create the LLM provider implied by config."""
+    model = config.agents.defaults.model
+    provider_name = config.get_provider_name(model)
+    p = config.get_provider(model)
+    spec = find_by_name(provider_name) if provider_name else None
+    backend = spec.backend if spec else "openai_compat"
+
+    if backend == "azure_openai":
+        if not p or not p.api_key or not p.api_base:
+            raise ValueError("Azure OpenAI requires api_key and api_base in config.")
+    elif backend == "openai_compat" and not model.startswith("bedrock/"):
+        needs_key = not (p and p.api_key)
+        exempt = spec and (spec.is_oauth or spec.is_local or spec.is_direct)
+        if needs_key and not exempt:
+            raise ValueError(f"No API key configured for provider '{provider_name}'.")
+
+    if backend == "openai_codex":
+        from nanobot.providers.openai_codex_provider import OpenAICodexProvider
+
+        provider = OpenAICodexProvider(default_model=model)
+    elif backend == "azure_openai":
+        from nanobot.providers.azure_openai_provider import AzureOpenAIProvider
+
+        provider = AzureOpenAIProvider(
+            api_key=p.api_key,
+            api_base=p.api_base,
+            default_model=model,
+        )
+    elif backend == "github_copilot":
+        from nanobot.providers.github_copilot_provider import GitHubCopilotProvider
+
+        provider = GitHubCopilotProvider(default_model=model)
+    elif backend == "anthropic":
+        from nanobot.providers.anthropic_provider import AnthropicProvider
+
+        provider = AnthropicProvider(
+            api_key=p.api_key if p else None,
+            api_base=config.get_api_base(model),
+            default_model=model,
+            extra_headers=p.extra_headers if p else None,
+        )
+    else:
+        from nanobot.providers.openai_compat_provider import OpenAICompatProvider
+
+        provider = OpenAICompatProvider(
+            api_key=p.api_key if p else None,
+            api_base=config.get_api_base(model),
+            default_model=model,
+            extra_headers=p.extra_headers if p else None,
+            spec=spec,
+        )
+
+    defaults = config.agents.defaults
+    provider.generation = GenerationSettings(
+        temperature=defaults.temperature,
+        max_tokens=defaults.max_tokens,
+        reasoning_effort=defaults.reasoning_effort,
+    )
+    return provider
+
+
+def runtime_signature(config: Config) -> tuple[object, ...]:
+    """Return the config fields that affect the primary LLM runtime."""
+    model = config.agents.defaults.model
+    defaults = config.agents.defaults
+    return (
+        model,
+        defaults.provider,
+        config.get_provider_name(model),
+        config.get_api_key(model),
+        config.get_api_base(model),
+        defaults.max_tokens,
+        defaults.temperature,
+        defaults.reasoning_effort,
+        defaults.context_window_tokens,
+    )
+
+
+def build_agent_runtime(config: Config) -> AgentRuntime:
+    return AgentRuntime(
+        provider=make_provider(config),
+        model=config.agents.defaults.model,
+        context_window_tokens=config.agents.defaults.context_window_tokens,
+        signature=runtime_signature(config),
+    )
+
+
+def load_agent_runtime(config_path: Path | None = None) -> AgentRuntime:
+    from nanobot.config.loader import load_config, resolve_config_env_vars
+
+    return build_agent_runtime(resolve_config_env_vars(load_config(config_path)))

nanobot/channels/websocket.py

@@ -539,6 +539,12 @@ class WebSocketChannel(BaseChannel):
         if got == "/api/sessions":
             return self._handle_sessions_list(request)
 
+        if got == "/api/settings":
+            return self._handle_settings(request)
+
+        if got == "/api/settings/update":
+            return self._handle_settings_update(request)
+
         m = re.match(r"^/api/sessions/([^/]+)/messages$", got)
         if m:
             return self._handle_session_messages(request, m.group(1))
@@ -647,6 +653,75 @@ class WebSocketChannel(BaseChannel):
         ]
         return _http_json_response({"sessions": cleaned})
 
+    def _settings_payload(self, *, requires_restart: bool = False) -> dict[str, Any]:
+        from nanobot.config.loader import get_config_path, load_config
+        from nanobot.providers.registry import PROVIDERS, find_by_name
+
+        config = load_config()
+        defaults = config.agents.defaults
+        provider_name = config.get_provider_name(defaults.model) or defaults.provider
+        provider = config.get_provider(defaults.model)
+        selected_provider = provider_name
+        if defaults.provider != "auto":
+            spec = find_by_name(defaults.provider)
+            selected_provider = spec.name if spec else provider_name
+        return {
+            "agent": {
+                "model": defaults.model,
+                "provider": selected_provider,
+                "resolved_provider": provider_name,
+                "has_api_key": bool(provider and provider.api_key),
+            },
+            "providers": [
+                {"name": "auto", "label": "Auto"}
+            ] + [
+                {"name": spec.name, "label": spec.label}
+                for spec in PROVIDERS
+            ],
+            "runtime": {
+                "config_path": str(get_config_path().expanduser()),
+            },
+            "requires_restart": requires_restart,
+        }
+
+    def _handle_settings(self, request: WsRequest) -> Response:
+        if not self._check_api_token(request):
+            return _http_error(401, "Unauthorized")
+        return _http_json_response(self._settings_payload())
+
+    def _handle_settings_update(self, request: WsRequest) -> Response:
+        if not self._check_api_token(request):
+            return _http_error(401, "Unauthorized")
+        from nanobot.config.loader import load_config, save_config
+        from nanobot.providers.registry import find_by_name
+
+        query = _parse_query(request.path)
+        config = load_config()
+        defaults = config.agents.defaults
+        changed = False
+
+        model = _query_first(query, "model")
+        if model is not None:
+            model = model.strip()
+            if not model:
+                return _http_error(400, "model is required")
+            if defaults.model != model:
+                defaults.model = model
+                changed = True
+
+        provider = _query_first(query, "provider")
+        if provider is not None:
+            provider = provider.strip() or "auto"
+            if provider != "auto" and find_by_name(provider) is None:
+                return _http_error(400, "unknown provider")
+            if defaults.provider != provider:
+                defaults.provider = provider
+                changed = True
+
+        if changed:
+            save_config(config)
+        return _http_json_response(self._settings_payload(requires_restart=changed))
+
     @staticmethod
     def _is_webui_session_key(key: str) -> bool:
         """Return True when *key* belongs to the webui's websocket-only surface."""

nanobot/cli/commands.py

@@ -412,73 +412,13 @@ def _make_provider(config: Config):
 
     Routing is driven by ``ProviderSpec.backend`` in the registry.
     """
-    from nanobot.providers.base import GenerationSettings
-    from nanobot.providers.registry import find_by_name
+    from nanobot.agent.runtime import make_provider
 
-    model = config.agents.defaults.model
-    provider_name = config.get_provider_name(model)
-    p = config.get_provider(model)
-    spec = find_by_name(provider_name) if provider_name else None
-    backend = spec.backend if spec else "openai_compat"
-
-    # --- validation ---
-    if backend == "azure_openai":
-        if not p or not p.api_key or not p.api_base:
-            console.print("[red]Error: Azure OpenAI requires api_key and api_base.[/red]")
-            console.print("Set them in ~/.nanobot/config.json under providers.azure_openai section")
-            console.print("Use the model field to specify the deployment name.")
-            raise typer.Exit(1)
-    elif backend == "openai_compat" and not model.startswith("bedrock/"):
-        needs_key = not (p and p.api_key)
-        exempt = spec and (spec.is_oauth or spec.is_local or spec.is_direct)
-        if needs_key and not exempt:
-            console.print("[red]Error: No API key configured.[/red]")
-            console.print("Set one in ~/.nanobot/config.json under providers section")
-            raise typer.Exit(1)
-
-    # --- instantiation by backend ---
-    if backend == "openai_codex":
-        from nanobot.providers.openai_codex_provider import OpenAICodexProvider
-
-        provider = OpenAICodexProvider(default_model=model)
-    elif backend == "azure_openai":
-        from nanobot.providers.azure_openai_provider import AzureOpenAIProvider
-
-        provider = AzureOpenAIProvider(
-            api_key=p.api_key,
-            api_base=p.api_base,
-            default_model=model,
-        )
-    elif backend == "github_copilot":
-        from nanobot.providers.github_copilot_provider import GitHubCopilotProvider
-        provider = GitHubCopilotProvider(default_model=model)
-    elif backend == "anthropic":
-        from nanobot.providers.anthropic_provider import AnthropicProvider
-
-        provider = AnthropicProvider(
-            api_key=p.api_key if p else None,
-            api_base=config.get_api_base(model),
-            default_model=model,
-            extra_headers=p.extra_headers if p else None,
-        )
-    else:
-        from nanobot.providers.openai_compat_provider import OpenAICompatProvider
-
-        provider = OpenAICompatProvider(
-            api_key=p.api_key if p else None,
-            api_base=config.get_api_base(model),
-            default_model=model,
-            extra_headers=p.extra_headers if p else None,
-            spec=spec,
-        )
-
-    defaults = config.agents.defaults
-    provider.generation = GenerationSettings(
-        temperature=defaults.temperature,
-        max_tokens=defaults.max_tokens,
-        reasoning_effort=defaults.reasoning_effort,
-    )
-    return provider
+    try:
+        return make_provider(config)
+    except ValueError as exc:
+        console.print(f"[red]Error: {exc}[/red]")
+        raise typer.Exit(1) from exc
 
 
 def _load_runtime_config(config: str | None = None, workspace: str | None = None) -> Config:
@@ -656,6 +596,7 @@ def _run_gateway(
 ) -> None:
     """Shared gateway runtime; ``open_browser_url`` opens a tab once channels are up."""
     from nanobot.agent.loop import AgentLoop
+    from nanobot.agent.runtime import build_agent_runtime, load_agent_runtime
     from nanobot.bus.queue import MessageBus
     from nanobot.channels.manager import ChannelManager
     from nanobot.cron.service import CronService
@@ -668,7 +609,12 @@ def _run_gateway(
     console.print(f"{__logo__} Starting nanobot gateway version {__version__} on port {port}...")
     sync_workspace_templates(config.workspace_path)
     bus = MessageBus()
-    provider = _make_provider(config)
+    try:
+        runtime = build_agent_runtime(config)
+    except ValueError as exc:
+        console.print(f"[red]Error: {exc}[/red]")
+        raise typer.Exit(1) from exc
+    provider = runtime.provider
     session_manager = SessionManager(config.workspace_path)
 
     # Preserve existing single-workspace installs, but keep custom workspaces clean.
@@ -684,9 +630,9 @@ def _run_gateway(
         bus=bus,
         provider=provider,
         workspace=config.workspace_path,
-        model=config.agents.defaults.model,
+        model=runtime.model,
         max_iterations=config.agents.defaults.max_tool_iterations,
-        context_window_tokens=config.agents.defaults.context_window_tokens,
+        context_window_tokens=runtime.context_window_tokens,
         web_config=config.tools.web,
         context_block_limit=config.agents.defaults.context_block_limit,
         max_tool_result_chars=config.agents.defaults.max_tool_result_chars,
@@ -702,6 +648,8 @@ def _run_gateway(
         disabled_skills=config.agents.defaults.disabled_skills,
         session_ttl_minutes=config.agents.defaults.session_ttl_minutes,
         tools_config=config.tools,
+        runtime_loader=load_agent_runtime,
+        runtime_signature=runtime.signature,
     )
 
     # Set cron callback (needs agent)

nanobot/nanobot.py

@@ -119,62 +119,6 @@ class Nanobot:
 
 def _make_provider(config: Any) -> Any:
     """Create the LLM provider from config (extracted from CLI)."""
-    from nanobot.providers.base import GenerationSettings
-    from nanobot.providers.registry import find_by_name
+    from nanobot.agent.runtime import make_provider
 
-    model = config.agents.defaults.model
-    provider_name = config.get_provider_name(model)
-    p = config.get_provider(model)
-    spec = find_by_name(provider_name) if provider_name else None
-    backend = spec.backend if spec else "openai_compat"
-
-    if backend == "azure_openai":
-        if not p or not p.api_key or not p.api_base:
-            raise ValueError("Azure OpenAI requires api_key and api_base in config.")
-    elif backend == "openai_compat" and not model.startswith("bedrock/"):
-        needs_key = not (p and p.api_key)
-        exempt = spec and (spec.is_oauth or spec.is_local or spec.is_direct)
-        if needs_key and not exempt:
-            raise ValueError(f"No API key configured for provider '{provider_name}'.")
-
-    if backend == "openai_codex":
-        from nanobot.providers.openai_codex_provider import OpenAICodexProvider
-
-        provider = OpenAICodexProvider(default_model=model)
-    elif backend == "github_copilot":
-        from nanobot.providers.github_copilot_provider import GitHubCopilotProvider
-
-        provider = GitHubCopilotProvider(default_model=model)
-    elif backend == "azure_openai":
-        from nanobot.providers.azure_openai_provider import AzureOpenAIProvider
-
-        provider = AzureOpenAIProvider(
-            api_key=p.api_key, api_base=p.api_base, default_model=model
-        )
-    elif backend == "anthropic":
-        from nanobot.providers.anthropic_provider import AnthropicProvider
-
-        provider = AnthropicProvider(
-            api_key=p.api_key if p else None,
-            api_base=config.get_api_base(model),
-            default_model=model,
-            extra_headers=p.extra_headers if p else None,
-        )
-    else:
-        from nanobot.providers.openai_compat_provider import OpenAICompatProvider
-
-        provider = OpenAICompatProvider(
-            api_key=p.api_key if p else None,
-            api_base=config.get_api_base(model),
-            default_model=model,
-            extra_headers=p.extra_headers if p else None,
-            spec=spec,
-        )
-
-    defaults = config.agents.defaults
-    provider.generation = GenerationSettings(
-        temperature=defaults.temperature,
-        max_tokens=defaults.max_tokens,
-        reasoning_effort=defaults.reasoning_effort,
-    )
-    return provider
+    return make_provider(config)

tests/agent/test_runtime_refresh.py

@@ -0,0 +1,49 @@
+from pathlib import Path
+from types import SimpleNamespace
+from unittest.mock import MagicMock
+
+from nanobot.agent.loop import AgentLoop
+from nanobot.agent.runtime import AgentRuntime
+from nanobot.bus.queue import MessageBus
+
+
+def _provider(default_model: str, max_tokens: int = 123) -> MagicMock:
+    provider = MagicMock()
+    provider.get_default_model.return_value = default_model
+    provider.generation = SimpleNamespace(max_tokens=max_tokens)
+    return provider
+
+
+def test_runtime_refresh_updates_loop_dependents(tmp_path: Path) -> None:
+    old_provider = _provider("old-model")
+    new_provider = _provider("new-model", max_tokens=456)
+    loop = AgentLoop(
+        bus=MessageBus(),
+        provider=old_provider,
+        workspace=tmp_path,
+        model="old-model",
+        context_window_tokens=1000,
+        runtime_loader=lambda: AgentRuntime(
+            provider=new_provider,
+            model="new-model",
+            context_window_tokens=2000,
+            signature=("new-model",),
+        ),
+    )
+
+    loop._refresh_runtime()
+
+    assert loop.provider is new_provider
+    assert loop.model == "new-model"
+    assert loop.context_window_tokens == 2000
+    assert loop.runner.provider is new_provider
+    assert loop.subagents.provider is new_provider
+    assert loop.subagents.model == "new-model"
+    assert loop.subagents.runner.provider is new_provider
+    assert loop.consolidator.provider is new_provider
+    assert loop.consolidator.model == "new-model"
+    assert loop.consolidator.context_window_tokens == 2000
+    assert loop.consolidator.max_completion_tokens == 456
+    assert loop.dream.provider is new_provider
+    assert loop.dream.model == "new-model"
+    assert loop.dream._runner.provider is new_provider

tests/channels/test_websocket_channel.py

@@ -26,6 +26,8 @@ from nanobot.channels.websocket import (
     _parse_query,
     _parse_request_path,
 )
+from nanobot.config.loader import load_config, save_config
+from nanobot.config.schema import Config
 
 # -- Shared helpers (aligned with test_websocket_integration.py) ---------------
 
@@ -439,6 +441,72 @@ async def test_http_route_issues_token_then_websocket_requires_it(bus: MagicMock
         await server_task
 
 
+@pytest.mark.asyncio
+async def test_settings_api_returns_safe_subset_and_updates_whitelist(
+    bus: MagicMock,
+    monkeypatch,
+    tmp_path,
+) -> None:
+    port = 29891
+    config_path = tmp_path / "config.json"
+    config = Config()
+    config.agents.defaults.model = "openai/gpt-4o"
+    config.providers.openai.api_key = "secret-key"
+    save_config(config, config_path)
+    monkeypatch.setattr("nanobot.config.loader._current_config_path", config_path)
+
+    channel = _ch(bus, port=port)
+    channel._api_tokens["tok"] = time.monotonic() + 300
+
+    server_task = asyncio.create_task(channel.start())
+    await asyncio.sleep(0.3)
+
+    try:
+        settings = await _http_get(
+            f"http://127.0.0.1:{port}/api/settings",
+            headers={"Authorization": "Bearer tok"},
+        )
+        assert settings.status_code == 200
+        body = settings.json()
+        assert body["agent"]["model"] == "openai/gpt-4o"
+        assert body["agent"]["provider"] == "openai"
+        assert {"name": "auto", "label": "Auto"} in body["providers"]
+        assert body["agent"]["has_api_key"] is True
+        assert "secret-key" not in settings.text
+
+        updated = await _http_get(
+            "http://127.0.0.1:"
+            f"{port}/api/settings/update?model=openrouter/test"
+            "&provider=openrouter",
+            headers={"Authorization": "Bearer tok"},
+        )
+        assert updated.status_code == 200
+        assert updated.json()["requires_restart"] is True
+
+        saved = load_config(config_path)
+        assert saved.agents.defaults.model == "openrouter/test"
+        assert saved.agents.defaults.provider == "openrouter"
+    finally:
+        await channel.stop()
+        await server_task
+
+
+def test_settings_payload_normalizes_camel_case_provider(
+    bus: MagicMock,
+    monkeypatch,
+    tmp_path,
+) -> None:
+    config_path = tmp_path / "config.json"
+    config = Config()
+    config.agents.defaults.provider = "minimaxAnthropic"
+    save_config(config, config_path)
+    monkeypatch.setattr("nanobot.config.loader._current_config_path", config_path)
+
+    body = _ch(bus)._settings_payload()
+
+    assert body["agent"]["provider"] == "minimax_anthropic"
+
+
 @pytest.mark.asyncio
 async def test_end_to_end_server_pushes_streaming_deltas_to_client(bus: MagicMock) -> None:
     port = 29880

webui/src/App.tsx

@@ -2,6 +2,7 @@ import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { DeleteConfirm } from "@/components/DeleteConfirm";
 import { Sidebar } from "@/components/Sidebar";
+import { SettingsView } from "@/components/settings/SettingsView";
 import { ThreadShell } from "@/components/thread/ThreadShell";
 import { Sheet, SheetContent } from "@/components/ui/sheet";
 import { preloadMarkdownText } from "@/components/MarkdownText";
@@ -25,6 +26,7 @@ type BootState =
 
 const SIDEBAR_STORAGE_KEY = "nanobot-webui.sidebar";
 const SIDEBAR_WIDTH = 279;
+type ShellView = "chat" | "settings";
 
 function readSidebarOpen(): boolean {
   if (typeof window === "undefined") return true;
@@ -136,22 +138,29 @@ export default function App() {
     );
   }
 
+  const handleModelNameChange = (modelName: string | null) => {
+    setState((current) =>
+      current.status === "ready" ? { ...current, modelName } : current,
+    );
+  };
+
   return (
     <ClientProvider
       client={state.client}
       token={state.token}
       modelName={state.modelName}
     >
-      <Shell />
+      <Shell onModelNameChange={handleModelNameChange} />
     </ClientProvider>
   );
 }
 
-function Shell() {
+function Shell({ onModelNameChange }: { onModelNameChange: (modelName: string | null) => void }) {
   const { t, i18n } = useTranslation();
   const { theme, toggle } = useTheme();
   const { sessions, loading, refresh, createChat, deleteChat } = useSessions();
   const [activeKey, setActiveKey] = useState<string | null>(null);
+  const [view, setView] = useState<ShellView>("chat");
   const [desktopSidebarOpen, setDesktopSidebarOpen] =
     useState<boolean>(readSidebarOpen);
   const [mobileSidebarOpen, setMobileSidebarOpen] = useState(false);
@@ -208,6 +217,7 @@ function Shell() {
     try {
       const chatId = await createChat();
       setActiveKey(`websocket:${chatId}`);
+      setView("chat");
       setMobileSidebarOpen(false);
       return chatId;
     } catch (e) {
@@ -219,6 +229,7 @@ function Shell() {
   const onSelectChat = useCallback(
     (key: string) => {
       setActiveKey(key);
+      setView("chat");
       setMobileSidebarOpen(false);
     },
     [],
@@ -266,6 +277,11 @@ function Shell() {
     onRefresh: () => void refresh(),
     onRequestDelete: (key: string, label: string) =>
       setPendingDelete({ key, label }),
+    activeView: view,
+    onOpenSettings: () => {
+      setView("settings" as const);
+      setMobileSidebarOpen(false);
+    },
   };
 
   return (
@@ -303,14 +319,23 @@ function Shell() {
       </Sheet>
 
       <main className="flex h-full min-w-0 flex-1 flex-col">
-        <ThreadShell
-          session={activeSession}
-          title={headerTitle}
-          onToggleSidebar={toggleSidebar}
-          onGoHome={() => setActiveKey(null)}
-          onNewChat={onNewChat}
-          hideSidebarToggleOnDesktop={desktopSidebarOpen}
-        />
+        {view === "settings" ? (
+          <SettingsView
+            theme={theme}
+            onToggleTheme={toggle}
+            onBackToChat={() => setView("chat")}
+            onModelNameChange={onModelNameChange}
+          />
+        ) : (
+          <ThreadShell
+            session={activeSession}
+            title={headerTitle}
+            onToggleSidebar={toggleSidebar}
+            onGoHome={() => setActiveKey(null)}
+            onNewChat={onNewChat}
+            hideSidebarToggleOnDesktop={desktopSidebarOpen}
+          />
+        )}
       </main>
 
       <DeleteConfirm

webui/src/components/Sidebar.tsx

@@ -1,9 +1,8 @@
-import { Moon, PanelLeftClose, Plus, RefreshCcw, Sun } from "lucide-react";
+import { Moon, PanelLeftClose, RefreshCcw, Settings, SquarePen, Sun } from "lucide-react";
 import { useTranslation } from "react-i18next";
 
 import { ChatList } from "@/components/ChatList";
 import { ConnectionBadge } from "@/components/ConnectionBadge";
-import { LanguageSwitcher } from "@/components/LanguageSwitcher";
 import { Button } from "@/components/ui/button";
 import { Separator } from "@/components/ui/separator";
 import type { ChatSummary } from "@/lib/types";
@@ -19,48 +18,60 @@ interface SidebarProps {
   onRefresh: () => void;
   onRequestDelete: (key: string, label: string) => void;
   onCollapse: () => void;
+  activeView?: "chat" | "settings";
+  onOpenSettings: () => void;
 }
 
 export function Sidebar(props: SidebarProps) {
   const { t } = useTranslation();
   return (
     <aside className="flex h-full w-full flex-col border-r border-sidebar-border/70 bg-sidebar text-sidebar-foreground">
-      <div className="flex items-center justify-between px-2 py-2">
-        <Button
-          variant="ghost"
-          size="icon"
-          aria-label={t("sidebar.collapse")}
-          onClick={props.onCollapse}
-          className="h-7 w-7 rounded-lg text-muted-foreground hover:bg-sidebar-accent hover:text-sidebar-foreground"
-        >
-          <PanelLeftClose className="h-3.5 w-3.5" />
-        </Button>
-        <Button
-          variant="ghost"
-          size="icon"
-          aria-label={t("sidebar.toggleTheme")}
-          onClick={props.onToggleTheme}
-          className="h-7 w-7 rounded-lg text-muted-foreground hover:bg-sidebar-accent hover:text-sidebar-foreground"
-        >
-          {props.theme === "dark" ? (
-            <Sun className="h-3.5 w-3.5" />
-          ) : (
-            <Moon className="h-3.5 w-3.5" />
-          )}
-        </Button>
+      <div className="flex items-center justify-between px-3 pb-2 pt-3">
+        <picture className="block min-w-0">
+          <source srcSet="/brand/nanobot_logo.webp" type="image/webp" />
+          <img
+            src="/brand/nanobot_logo.png"
+            alt="nanobot"
+            className="h-7 w-auto select-none object-contain"
+            draggable={false}
+          />
+        </picture>
+        <div className="flex items-center gap-0.5">
+          <Button
+            variant="ghost"
+            size="icon"
+            aria-label={t("sidebar.toggleTheme")}
+            onClick={props.onToggleTheme}
+            className="h-7 w-7 rounded-lg text-muted-foreground hover:bg-sidebar-accent hover:text-sidebar-foreground"
+          >
+            {props.theme === "dark" ? (
+              <Sun className="h-3.5 w-3.5" />
+            ) : (
+              <Moon className="h-3.5 w-3.5" />
+            )}
+          </Button>
+          <Button
+            variant="ghost"
+            size="icon"
+            aria-label={t("sidebar.collapse")}
+            onClick={props.onCollapse}
+            className="h-7 w-7 rounded-lg text-muted-foreground hover:bg-sidebar-accent hover:text-sidebar-foreground"
+          >
+            <PanelLeftClose className="h-3.5 w-3.5" />
+          </Button>
+        </div>
       </div>
-      <div className="px-2 pb-2.5">
+      <div className="px-2 pb-2">
         <Button
           onClick={props.onNewChat}
-          className="h-8.5 w-full justify-start gap-2 rounded-lg border border-sidebar-border/80 bg-card/25 px-3 text-[13px] font-medium text-sidebar-foreground shadow-none hover:bg-sidebar-accent/80"
-          variant="outline"
+          className="h-9 w-full justify-start gap-2 rounded-full px-3 text-[13px] font-medium text-sidebar-foreground/90 hover:bg-sidebar-accent hover:text-sidebar-foreground"
+          variant="ghost"
         >
-          <Plus className="h-3.5 w-3.5" />
+          <SquarePen className="h-3.5 w-3.5" />
           {t("sidebar.newChat")}
         </Button>
       </div>
-      <Separator className="bg-sidebar-border/70" />
-      <div className="flex items-center justify-between px-2.5 py-2 text-[11px] font-medium text-muted-foreground">
+      <div className="flex items-center justify-between px-3 pb-1.5 pt-2.5 text-[11px] font-medium text-muted-foreground">
         <span>{t("sidebar.recent")}</span>
         <Button
           variant="ghost"
@@ -81,10 +92,17 @@ export function Sidebar(props: SidebarProps) {
           onRequestDelete={props.onRequestDelete}
         />
       </div>
-      <Separator className="bg-sidebar-border/70" />
+      <Separator className="bg-sidebar-border/50" />
       <div className="flex items-center justify-between gap-2 px-2.5 py-2 text-xs">
         <ConnectionBadge />
-        <LanguageSwitcher />
+        <Button
+          onClick={props.onOpenSettings}
+          className="h-7 gap-1.5 rounded-md px-2 text-[11px] text-muted-foreground hover:bg-sidebar-accent hover:text-sidebar-foreground"
+          variant={props.activeView === "settings" ? "secondary" : "ghost"}
+        >
+          <Settings className="h-3.5 w-3.5" />
+          Settings
+        </Button>
       </div>
     </aside>
   );

webui/src/components/settings/SettingsView.tsx

@@ -0,0 +1,245 @@
+import { useCallback, useEffect, useMemo, useState } from "react";
+import { ChevronLeft, Loader2 } from "lucide-react";
+
+import { LanguageSwitcher } from "@/components/LanguageSwitcher";
+import { Button } from "@/components/ui/button";
+import { Input } from "@/components/ui/input";
+import { fetchSettings, updateSettings } from "@/lib/api";
+import { cn } from "@/lib/utils";
+import { useClient } from "@/providers/ClientProvider";
+import type { SettingsPayload } from "@/lib/types";
+
+interface SettingsViewProps {
+  theme: "light" | "dark";
+  onToggleTheme: () => void;
+  onBackToChat: () => void;
+  onModelNameChange: (modelName: string | null) => void;
+}
+
+export function SettingsView({
+  onBackToChat,
+  onModelNameChange,
+}: SettingsViewProps) {
+  const { token } = useClient();
+  const [settings, setSettings] = useState<SettingsPayload | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [saving, setSaving] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+  const [form, setForm] = useState({
+    model: "",
+    provider: "auto",
+  });
+
+  const applyPayload = useCallback((payload: SettingsPayload) => {
+    setSettings(payload);
+    setForm({
+      model: payload.agent.model,
+      provider: payload.agent.provider,
+    });
+  }, []);
+
+  useEffect(() => {
+    let cancelled = false;
+    setLoading(true);
+    fetchSettings(token)
+      .then((payload) => {
+        if (!cancelled) {
+          applyPayload(payload);
+          setError(null);
+        }
+      })
+      .catch((err) => {
+        if (!cancelled) setError((err as Error).message);
+      })
+      .finally(() => {
+        if (!cancelled) setLoading(false);
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, [applyPayload, token]);
+
+  const dirty = useMemo(() => {
+    if (!settings) return false;
+    return (
+      form.model !== settings.agent.model ||
+      form.provider !== settings.agent.provider
+    );
+  }, [form, settings]);
+
+  const save = async () => {
+    if (!dirty || saving) return;
+    setSaving(true);
+    try {
+      const payload = await updateSettings(token, form);
+      applyPayload(payload);
+      onModelNameChange(payload.agent.model || null);
+      setError(null);
+    } catch (err) {
+      setError((err as Error).message);
+    } finally {
+      setSaving(false);
+    }
+  };
+
+  return (
+    <div className="min-h-0 flex-1 overflow-y-auto bg-background">
+      <main className="mx-auto w-full max-w-[1000px] px-6 py-6">
+        <button
+          type="button"
+          onClick={onBackToChat}
+          className="mb-4 inline-flex items-center gap-1.5 text-xs font-medium text-muted-foreground hover:text-foreground"
+        >
+          <ChevronLeft className="h-3.5 w-3.5" />
+          Back to chat
+        </button>
+
+        <h1 className="mb-6 text-base font-semibold tracking-tight">General</h1>
+
+        {loading ? (
+          <div className="flex h-48 items-center justify-center text-sm text-muted-foreground">
+            <Loader2 className="mr-2 h-4 w-4 animate-spin" />
+            Loading settings...
+          </div>
+        ) : error ? (
+          <SettingsGroup>
+            <SettingsRow title="Could not load settings">
+              <span className="max-w-[520px] text-sm text-muted-foreground">{error}</span>
+            </SettingsRow>
+          </SettingsGroup>
+        ) : settings ? (
+          <SettingsSection
+            form={form}
+            setForm={setForm}
+            settings={settings}
+            dirty={dirty}
+            saving={saving}
+            onSave={save}
+          />
+        ) : null}
+      </main>
+    </div>
+  );
+}
+
+function SettingsSection({
+  form,
+  setForm,
+  settings,
+  dirty,
+  saving,
+  onSave,
+}: {
+  form: {
+    model: string;
+    provider: string;
+  };
+  setForm: React.Dispatch<React.SetStateAction<{
+    model: string;
+    provider: string;
+  }>>;
+  settings: SettingsPayload;
+  dirty: boolean;
+  saving: boolean;
+  onSave: () => void;
+}) {
+  return (
+    <div className="space-y-7">
+      <section>
+        <h2 className="mb-2 px-2 text-xs font-medium text-muted-foreground">AI</h2>
+        <SettingsGroup>
+          <SettingsRow title="Provider">
+            <select
+              value={form.provider}
+              onChange={(event) => setForm((prev) => ({ ...prev, provider: event.target.value }))}
+              className={cn(
+                "h-8 w-[210px] rounded-md border border-input bg-background px-2 text-sm",
+                "outline-none transition-colors hover:bg-accent focus-visible:ring-2 focus-visible:ring-ring",
+              )}
+            >
+              {settings.providers.map((provider) => (
+                <option key={provider.name} value={provider.name}>
+                  {provider.label}
+                </option>
+              ))}
+            </select>
+          </SettingsRow>
+
+          <SettingsRow title="Model">
+            <Input
+              value={form.model}
+              onChange={(event) => setForm((prev) => ({ ...prev, model: event.target.value }))}
+              className="h-8 w-[280px]"
+            />
+          </SettingsRow>
+
+          {(dirty || saving || settings.requires_restart) ? (
+            <SettingsFooter
+              dirty={dirty}
+              saving={saving}
+              saved={settings.requires_restart && !dirty}
+              onSave={onSave}
+            />
+          ) : null}
+        </SettingsGroup>
+      </section>
+
+      <section>
+        <h2 className="mb-2 px-2 text-xs font-medium text-muted-foreground">Interface</h2>
+        <SettingsGroup>
+          <SettingsRow title="Language">
+            <LanguageSwitcher />
+          </SettingsRow>
+        </SettingsGroup>
+      </section>
+    </div>
+  );
+}
+
+function SettingsGroup({ children }: { children: React.ReactNode }) {
+  return (
+    <div className="overflow-hidden rounded-xl border border-border/60 bg-card/80">
+      <div className="divide-y divide-border/50">{children}</div>
+    </div>
+  );
+}
+
+function SettingsRow({
+  title,
+  children,
+}: {
+  title: string;
+  children?: React.ReactNode;
+}) {
+  return (
+    <div className="flex min-h-[52px] flex-col gap-3 px-3 py-2.5 sm:flex-row sm:items-center sm:justify-between">
+      <div className="min-w-0">
+        <div className="text-sm font-medium leading-5">{title}</div>
+      </div>
+      {children ? <div className="shrink-0 sm:ml-6">{children}</div> : null}
+    </div>
+  );
+}
+
+function SettingsFooter({
+  dirty,
+  saving,
+  saved,
+  onSave,
+}: {
+  dirty: boolean;
+  saving: boolean;
+  saved: boolean;
+  onSave: () => void;
+}) {
+  return (
+    <div className="flex min-h-[52px] items-center justify-between gap-4 px-3 py-2.5">
+      <div className="text-sm text-muted-foreground">
+        {saved ? "Saved. Restart nanobot to apply." : "Unsaved changes."}
+      </div>
+      <Button size="sm" variant="outline" onClick={onSave} disabled={!dirty || saving}>
+        {saving ? "Saving" : "Save"}
+      </Button>
+    </div>
+  );
+}

webui/src/lib/api.ts

@@ -1,4 +1,4 @@
-import type { ChatSummary } from "./types";
+import type { ChatSummary, SettingsPayload, SettingsUpdate } from "./types";
 
 export class ApiError extends Error {
   status: number;
@@ -104,3 +104,21 @@ export async function deleteSession(
   );
   return body.deleted;
 }
+
+export async function fetchSettings(
+  token: string,
+  base: string = "",
+): Promise<SettingsPayload> {
+  return request<SettingsPayload>(`${base}/api/settings`, token);
+}
+
+export async function updateSettings(
+  token: string,
+  update: SettingsUpdate,
+  base: string = "",
+): Promise<SettingsPayload> {
+  const query = new URLSearchParams();
+  if (update.model !== undefined) query.set("model", update.model);
+  if (update.provider !== undefined) query.set("provider", update.provider);
+  return request<SettingsPayload>(`${base}/api/settings/update?${query}`, token);
+}

webui/src/lib/types.ts

@@ -66,6 +66,28 @@ export interface BootstrapResponse {
   model_name?: string | null;
 }
 
+export interface SettingsPayload {
+  agent: {
+    model: string;
+    provider: string;
+    resolved_provider: string | null;
+    has_api_key: boolean;
+  };
+  providers: Array<{
+    name: string;
+    label: string;
+  }>;
+  runtime: {
+    config_path: string;
+  };
+  requires_restart: boolean;
+}
+
+export interface SettingsUpdate {
+  model?: string;
+  provider?: string;
+}
+
 export type ConnectionStatus =
   | "idle"
   | "connecting"

webui/src/tests/api.test.ts

@@ -1,6 +1,6 @@
 import { beforeEach, describe, expect, it, vi } from "vitest";
 
-import { deleteSession, fetchSessionMessages } from "@/lib/api";
+import { deleteSession, fetchSessionMessages, updateSettings } from "@/lib/api";
 
 describe("webui API helpers", () => {
   beforeEach(() => {
@@ -34,4 +34,18 @@ describe("webui API helpers", () => {
       }),
     );
   });
+
+  it("serializes settings updates as a narrow query string", async () => {
+    await updateSettings("tok", {
+      model: "openrouter/test",
+      provider: "openrouter",
+    });
+
+    expect(fetch).toHaveBeenCalledWith(
+      "/api/settings/update?model=openrouter%2Ftest&provider=openrouter",
+      expect.objectContaining({
+        headers: { Authorization: "Bearer tok" },
+      }),
+    );
+  });
 });

webui/src/tests/app-layout.test.tsx

@@ -146,4 +146,44 @@ describe("App layout", () => {
     expect(screen.queryByText('Delete “First chat”?')).not.toBeInTheDocument();
     expect(document.body.style.pointerEvents).not.toBe("none");
   }, 15_000);
+
+  it("opens the Cursor-style settings view from the sidebar", async () => {
+    vi.stubGlobal(
+      "fetch",
+      vi.fn(async (input: RequestInfo | URL) => {
+        if (String(input).includes("/api/settings")) {
+          return {
+            ok: true,
+            status: 200,
+            json: async () => ({
+              agent: {
+                model: "openai/gpt-4o",
+                provider: "auto",
+                resolved_provider: "openai",
+                has_api_key: true,
+              },
+              providers: [
+                { name: "auto", label: "Auto" },
+                { name: "openai", label: "OpenAI" },
+              ],
+              runtime: {
+                config_path: "/tmp/config.json",
+              },
+              requires_restart: false,
+            }),
+          };
+        }
+        return { ok: false, status: 404, json: async () => ({}) };
+      }),
+    );
+
+    render(<App />);
+
+    await waitFor(() => expect(connectSpy).toHaveBeenCalled());
+    fireEvent.click(screen.getByRole("button", { name: "Settings" }));
+
+    expect(await screen.findByRole("heading", { name: "General" })).toBeInTheDocument();
+    expect(screen.getByText("AI")).toBeInTheDocument();
+    expect(screen.getByDisplayValue("openai/gpt-4o")).toBeInTheDocument();
+  });
 });