fix: persist TUI model selection defaults (#24)

* Persist runtime model and default thinking

* fix: persist model defaults from TUI

* refactor: centralize default thinking resolution

* fix: wait for background shutdown notifications

* Revert "fix: wait for background shutdown notifications"

This reverts commit cf98059b8d.

* test: remove SDK default thinking case

* fix: respect thinking mode off defaults

* fix: normalize runtime thinking requests

.changeset/persist-runtime-model-defaults.md

@@ -0,0 +1,6 @@
+---
+"@moonshot-ai/agent-core": patch
+"@moonshot-ai/kimi-code": patch
+---
+
+Persist model selections from the terminal UI to the default configuration, and honor the configured default thinking state for new sessions.

apps/kimi-code/src/tui/kimi-tui.ts

@@ -4349,20 +4349,16 @@ export class KimiTUI {
       return;
     }
 
-    if (alias === this.state.appState.model && thinking === this.state.appState.thinking) {
-      this.showStatus(`Already using ${alias} with thinking ${thinking ? 'on' : 'off'}.`);
-      return;
-    }
-
     const level = thinking ? 'on' : 'off';
     const prevModel = this.state.appState.model;
     const prevThinking = this.state.appState.thinking;
+    const runtimeChanged = alias !== prevModel || thinking !== prevThinking;
 
+    const session = this.session;
     try {
-      const session = this.session;
-      if (session === undefined) {
+      if (session === undefined && runtimeChanged) {
         await this.activateModelAfterLogin(alias, thinking);
-      } else {
+      } else if (session !== undefined) {
         if (alias !== prevModel) {
           await session.setModel(alias);
         }
@@ -4370,23 +4366,50 @@ export class KimiTUI {
           await session.setThinking(level);
         }
       }
-      this.setAppState({ model: alias, thinking });
-      if (session === undefined) {
-        if (alias !== prevModel) {
-          this.track('model_switch', { model: alias });
-        }
-        if (thinking !== prevThinking) {
-          this.track('thinking_toggle', { enabled: thinking });
-        }
-      }
-      this.showStatus(
-        `Switched to ${alias} with thinking ${level}.`,
-        this.state.theme.colors.success,
-      );
     } catch (error) {
       const msg = formatErrorMessage(error);
       this.showError(`Failed to switch model: ${msg}`);
+      return;
     }
+
+    this.setAppState({ model: alias, thinking });
+    if (session === undefined && runtimeChanged) {
+      if (alias !== prevModel) {
+        this.track('model_switch', { model: alias });
+      }
+      if (thinking !== prevThinking) {
+        this.track('thinking_toggle', { enabled: thinking });
+      }
+    }
+
+    let persisted = false;
+    try {
+      persisted = await this.persistModelSelection(alias, thinking);
+    } catch (error) {
+      const msg = formatErrorMessage(error);
+      this.showError(`Switched to ${alias}, but failed to save default: ${msg}`);
+      return;
+    }
+
+    const status = runtimeChanged
+      ? `Switched to ${alias} with thinking ${level}.`
+      : persisted
+        ? `Saved ${alias} with thinking ${level} as default.`
+        : `Already using ${alias} with thinking ${level}.`;
+    this.showStatus(status, this.state.theme.colors.success);
+  }
+
+  // Persists the selected model and thinking state as the startup defaults.
+  private async persistModelSelection(alias: string, thinking: boolean): Promise<boolean> {
+    const config = await this.harness.getConfig({ reload: true });
+    if (config.defaultModel === alias && config.defaultThinking === thinking) {
+      return false;
+    }
+    await this.harness.setConfig({
+      defaultModel: alias,
+      defaultThinking: thinking,
+    });
+    return true;
   }
 
   // Shows the theme selector.

apps/kimi-code/test/tui/kimi-tui-message-flow.test.ts

@@ -117,6 +117,7 @@ function makeHarness(session = makeSession(), overrides: Record<string, unknown>
         k2: { model: 'moonshot-v1', maxContextSize: 100 },
       },
     })),
+    setConfig: vi.fn(async () => ({ providers: {} })),
     createSession: vi.fn(async () => session),
     resumeSession: vi.fn(async () => session),
     forkSession: vi.fn(async () => session),
@@ -1026,6 +1027,7 @@ describe('KimiTUI message flow', () => {
 
   it('applies /model selection with inline thinking state', async () => {
     const session = makeSession();
+    const setConfig = vi.fn(async () => ({ providers: {} }));
     const { driver } = await makeDriver(session, {
       getConfig: vi.fn(async () => ({
         models: {
@@ -1044,7 +1046,10 @@ describe('KimiTUI message flow', () => {
             capabilities: ['thinking'],
           },
         },
+        defaultModel: 'k2',
+        defaultThinking: false,
       })),
+      setConfig,
     });
 
     driver.handleUserInput('/model turbo');
@@ -1060,11 +1065,51 @@ describe('KimiTUI message flow', () => {
     await vi.waitFor(() => {
       expect(session.setModel).toHaveBeenCalledWith('turbo');
       expect(session.setThinking).toHaveBeenCalledWith('on');
+      expect(setConfig).toHaveBeenCalledWith({
+        defaultModel: 'turbo',
+        defaultThinking: true,
+      });
     });
     expect(driver.state.appState.model).toBe('turbo');
     expect(driver.state.appState.thinking).toBe(true);
   });
 
+  it('persists /model selection even when runtime state is unchanged', async () => {
+    const session = makeSession();
+    const setConfig = vi.fn(async () => ({ providers: {} }));
+    const { driver } = await makeDriver(session, {
+      getConfig: vi.fn(async () => ({
+        models: {
+          k2: {
+            provider: 'managed:kimi-code',
+            model: 'kimi-k2',
+            maxContextSize: 100,
+            displayName: 'Kimi K2',
+            capabilities: ['thinking'],
+          },
+        },
+        defaultModel: 'old-default',
+        defaultThinking: true,
+      })),
+      setConfig,
+    });
+
+    driver.handleUserInput('/model k2');
+
+    const picker = driver.state.editorContainer.children[0];
+    expect(picker).toBeInstanceOf(ModelSelectorComponent);
+    (picker as ModelSelectorComponent).handleInput('\r');
+
+    await vi.waitFor(() => {
+      expect(setConfig).toHaveBeenCalledWith({
+        defaultModel: 'k2',
+        defaultThinking: false,
+      });
+    });
+    expect(session.setModel).not.toHaveBeenCalled();
+    expect(session.setThinking).not.toHaveBeenCalled();
+  });
+
   it('deletes Kitty inline images when /new clears the transcript', async () => {
     setCapabilities({ images: 'kitty', trueColor: true, hyperlinks: true });
     const { driver, harness } = await makeDriver(makeSession({ id: 'ses-1' }));

packages/agent-core/src/providers/provider-manager.ts

@@ -113,7 +113,10 @@ export class ProviderManager {
   }
 
   resolveThinkingLevel(requestedThinking?: string): ThinkingEffort {
-    return resolveThinkingEffort(requestedThinking, this.state.config.thinking);
+    return resolveThinkingEffort(
+      resolveRuntimeThinkingRequest(requestedThinking, this.state.config.defaultThinking),
+      this.state.config.thinking,
+    );
   }
 
   resolveSelectedModel(requestedModel: string | undefined): string | undefined {
@@ -137,3 +140,12 @@ function normalizeString(value: string | undefined): string | undefined {
   const trimmed = value.trim();
   return trimmed.length > 0 ? trimmed : undefined;
 }
+
+function resolveRuntimeThinkingRequest(
+  requestedThinking: string | undefined,
+  defaultThinking: boolean | undefined,
+): string | undefined {
+  const normalized = normalizeString(requestedThinking);
+  if (normalized !== undefined) return normalized;
+  return defaultThinking === false ? 'off' : undefined;
+}

packages/agent-core/test/harness/runtime-provider.test.ts

@@ -585,16 +585,29 @@ describe('ProviderManager thinking level', () => {
     const manager = new ProviderManager({
       config: {
         providers: {},
+        defaultThinking: false,
         thinking: { effort: 'medium', mode: 'auto' },
       },
     });
     expect(manager.resolveThinkingLevel('on')).toBe('medium');
     expect(manager.resolveThinkingLevel('off')).toBe('off');
     expect(manager.resolveThinkingLevel('low')).toBe('low');
-    expect(manager.resolveThinkingLevel()).toBe('medium');
+    expect(manager.resolveThinkingLevel()).toBe('off');
+    expect(manager.resolveThinkingLevel('')).toBe('off');
+    expect(manager.resolveThinkingLevel('   ')).toBe('off');
+
+    const managerOnByDefault = new ProviderManager({
+      config: {
+        providers: {},
+        defaultThinking: true,
+        thinking: { effort: 'medium', mode: 'auto' },
+      },
+    });
+    expect(managerOnByDefault.resolveThinkingLevel()).toBe('medium');
+    expect(managerOnByDefault.resolveThinkingLevel('   ')).toBe('medium');
 
     const managerWithoutEffort = new ProviderManager({
-      config: { providers: {}, thinking: { mode: 'auto' } },
+      config: { providers: {}, defaultThinking: true, thinking: { mode: 'auto' } },
     });
     expect(managerWithoutEffort.resolveThinkingLevel('on')).toBe('high');
     expect(managerWithoutEffort.resolveThinkingLevel()).toBe('high');
@@ -604,6 +617,16 @@ describe('ProviderManager thinking level', () => {
     });
     expect(managerOffByDefault.resolveThinkingLevel()).toBe('off');
 
+    const managerWithModeOffAndDefaultThinking = new ProviderManager({
+      config: {
+        providers: {},
+        defaultThinking: true,
+        thinking: { effort: 'medium', mode: 'off' },
+      },
+    });
+    expect(managerWithModeOffAndDefaultThinking.resolveThinkingLevel()).toBe('off');
+    expect(managerWithModeOffAndDefaultThinking.resolveThinkingLevel('   ')).toBe('off');
+
     const managerWithoutThinking = new ProviderManager({ config: { providers: {} } });
     expect(managerWithoutThinking.resolveThinkingLevel()).toBe('high');
   });