diff --git a/.changeset/model-picker-keeps-effort.md b/.changeset/model-picker-keeps-effort.md
new file mode 100644
index 00000000..98f30eca
--- /dev/null
+++ b/.changeset/model-picker-keeps-effort.md
@@ -0,0 +1,5 @@
+---
+"@pythoughts/pythinker-code": patch
+---
+
+Keep the current thinking effort when switching models in the model picker instead of silently saving the new model's lowest level as the default, and repair a stale thinking mode in the config when saving an effort.
diff --git a/apps/pythinker-code/src/tui/components/dialogs/model-selector.ts b/apps/pythinker-code/src/tui/components/dialogs/model-selector.ts
index 5b9cc02c..45dc5a76 100644
--- a/apps/pythinker-code/src/tui/components/dialogs/model-selector.ts
+++ b/apps/pythinker-code/src/tui/components/dialogs/model-selector.ts
@@ -215,16 +215,14 @@ export class ModelSelectorComponent extends Container implements Focusable {
 
   /**
    * Effort draft for a model: an explicit ←/→ override when set, otherwise the
-   * live effort level for the active model, otherwise the first non-off level
-   * (or 'off' when the model does not support thinking).
+   * live effort level coerced to what the model supports. Defaulting other
+   * models to their first level instead would silently persist that level as
+   * the new startup default on switch, clobbering the user's saved effort.
    */
   private draftFor(choice: ModelChoice): string {
     const override = this.effortOverrides.get(choice.alias);
     if (override !== undefined) return override;
-    if (choice.alias === this.currentValue) {
-      return coerceEffortForModel(choice.model, this.opts.currentEffort);
-    }
-    return effortLevelsForModel(choice.model).find((level) => level !== 'off') ?? 'off';
+    return coerceEffortForModel(choice.model, this.opts.currentEffort);
   }
 
   handleInput(data: string): boolean {
diff --git a/apps/pythinker-code/src/tui/utils/persist-effort.ts b/apps/pythinker-code/src/tui/utils/persist-effort.ts
index f746c609..b6376c7e 100644
--- a/apps/pythinker-code/src/tui/utils/persist-effort.ts
+++ b/apps/pythinker-code/src/tui/utils/persist-effort.ts
@@ -10,18 +10,23 @@ export async function persistDefaultModelSelection(
   effort: string,
 ): Promise<boolean> {
   const defaultThinking = effort !== 'off';
+  // setConfig deep-merges, so a stale `mode = "off"` left in config.toml would
+  // survive an effort-only patch and force thinking off on the next startup.
+  // Write mode alongside effort to keep the pair consistent.
+  const mode = defaultThinking ? 'on' : 'off';
   const config = await harness.getConfig({ reload: true });
   if (
     config.defaultModel === alias &&
     config.defaultThinking === defaultThinking &&
-    config.thinking?.effort === effort
+    config.thinking?.effort === effort &&
+    config.thinking.mode === mode
   ) {
     return false;
   }
   await harness.setConfig({
     defaultModel: alias,
     defaultThinking,
-    thinking: { effort },
+    thinking: { effort, mode },
   });
   return true;
 }
diff --git a/apps/pythinker-code/test/tui/components/dialogs/model-selector.test.ts b/apps/pythinker-code/test/tui/components/dialogs/model-selector.test.ts
index 4bda19c8..1e3d58fb 100644
--- a/apps/pythinker-code/test/tui/components/dialogs/model-selector.test.ts
+++ b/apps/pythinker-code/test/tui/components/dialogs/model-selector.test.ts
@@ -217,6 +217,24 @@ describe('ModelSelectorComponent', () => {
     expect(onSelect).toHaveBeenLastCalledWith({ alias: 'plain', effort: 'off' });
   });
 
+  it('keeps the live effort when switching to another model instead of resetting to its first level', () => {
+    const onSelect = vi.fn();
+    const picker = new ModelSelectorComponent({
+      models: {
+        current: model('Kimi K2', ['thinking'], ['low', 'high', 'max']),
+        other: model('Kimi K3', ['thinking'], ['low', 'high', 'max']),
+      },
+      currentValue: 'current',
+      currentEffort: 'max',
+      onSelect,
+      onCancel: vi.fn(),
+    });
+
+    picker.handleInput(DOWN);
+    picker.handleInput('\r');
+    expect(onSelect).toHaveBeenLastCalledWith({ alias: 'other', effort: 'max' });
+  });
+
   it('clamps the live effort when it is not in the current model’s set', () => {
     const onSelect = vi.fn();
     const picker = new ModelSelectorComponent({
@@ -259,16 +277,16 @@ describe('ModelSelectorComponent', () => {
       onCancel: vi.fn(),
     });
 
-    picker.handleInput(DOWN); // -> thinking model (defaults to first non-off level)
-    picker.handleInput(RIGHT); // low -> medium
+    picker.handleInput(DOWN); // -> thinking model (keeps the live off state)
+    picker.handleInput(RIGHT); // off -> low
     picker.handleInput(UP); // -> plain
-    picker.handleInput(DOWN); // -> thinking (the medium override persists)
+    picker.handleInput(DOWN); // -> thinking (the low override persists)
     picker.handleInput('\r');
 
-    expect(onSelect).toHaveBeenCalledWith({ alias: 'thinking', effort: 'medium' });
+    expect(onSelect).toHaveBeenCalledWith({ alias: 'thinking', effort: 'low' });
   });
 
-  it('defaults a capable model to its first level but keeps the current model state', () => {
+  it('keeps the live off state when moving to another capable model', () => {
     const onSelect = vi.fn();
     const picker = new ModelSelectorComponent({
       models: {
@@ -284,10 +302,10 @@ describe('ModelSelectorComponent', () => {
     // The active model reflects its live (off) state.
     expect(text(picker)).toContain('[ off ]');
     picker.handleInput(DOWN); // -> the other thinking-capable model
-    // A capable, non-active model defaults to its first non-off level.
-    expect(text(picker)).toContain('[ med ]');
+    // A capable, non-active model keeps the live effort instead of resetting.
+    expect(text(picker)).toContain('[ off ]');
     picker.handleInput('\r');
-    expect(onSelect).toHaveBeenCalledWith({ alias: 'other', effort: 'medium' });
+    expect(onSelect).toHaveBeenCalledWith({ alias: 'other', effort: 'off' });
   });
 
   it('fuzzy-filters by typing and reports a match count', () => {
diff --git a/apps/pythinker-code/test/tui/components/dialogs/tabbed-model-selector.test.ts b/apps/pythinker-code/test/tui/components/dialogs/tabbed-model-selector.test.ts
index 43f81bd4..521a3e5c 100644
--- a/apps/pythinker-code/test/tui/components/dialogs/tabbed-model-selector.test.ts
+++ b/apps/pythinker-code/test/tui/components/dialogs/tabbed-model-selector.test.ts
@@ -190,6 +190,6 @@ describe('TabbedModelSelectorComponent', () => {
     expect(allLines).toHaveLength(1);
 
     component.handleInput('\r');
-    expect(onSelect).toHaveBeenCalledWith({ alias: 'terra/terra-13b', effort: 'low' });
+    expect(onSelect).toHaveBeenCalledWith({ alias: 'terra/terra-13b', effort: 'medium' });
   });
 });
diff --git a/apps/pythinker-code/test/tui/controllers/editor-keyboard.test.ts b/apps/pythinker-code/test/tui/controllers/editor-keyboard.test.ts
index a16e5c15..1f233fa4 100644
--- a/apps/pythinker-code/test/tui/controllers/editor-keyboard.test.ts
+++ b/apps/pythinker-code/test/tui/controllers/editor-keyboard.test.ts
@@ -54,7 +54,7 @@ describe('EditorKeyboardController thinking-effort cycling', () => {
       expect(setConfig).toHaveBeenCalledWith({
         defaultModel: 'test/model',
         defaultThinking: true,
-        thinking: { effort: 'medium' },
+        thinking: { effort: 'medium', mode: 'on' },
       });
     });
   });
diff --git a/apps/pythinker-code/test/tui/pythinker-tui-message-flow.test.ts b/apps/pythinker-code/test/tui/pythinker-tui-message-flow.test.ts
index fe787454..96e66d1b 100644
--- a/apps/pythinker-code/test/tui/pythinker-tui-message-flow.test.ts
+++ b/apps/pythinker-code/test/tui/pythinker-tui-message-flow.test.ts
@@ -5218,21 +5218,21 @@ command = "vim"
     expect(filteredOutput).toContain('Search: tu');
     expect(filteredOutput).toContain('Kimi Turbo');
     expect(filteredOutput).not.toContain('Kimi K2');
-    // Turbo is a thinking-capable model that is not the active one, so it
-    // defaults to its first non-off effort level without any ←/→ movement.
+    // Turbo is not the active model, but it keeps the live effort (off here)
+    // instead of resetting to its first level and persisting that as default.
     (picker as TabbedModelSelectorComponent).handleInput('\r');
 
     await vi.waitFor(() => {
       expect(session.setModel).toHaveBeenCalledWith('turbo');
-      expect(session.setThinking).toHaveBeenCalledWith('low');
       expect(setConfig).toHaveBeenCalledWith({
         defaultModel: 'turbo',
-        defaultThinking: true,
-        thinking: { effort: 'low' },
+        defaultThinking: false,
+        thinking: { effort: 'off', mode: 'off' },
       });
     });
+    expect(session.setThinking).not.toHaveBeenCalled();
     expect(driver.state.appState.model).toBe('turbo');
-    expect(driver.state.appState.thinkingLevel).toBe('low');
+    expect(driver.state.appState.thinkingLevel).toBe('off');
   });
 
   it('persists /model selection even when runtime state is unchanged', async () => {
@@ -5267,7 +5267,7 @@ command = "vim"
       expect(setConfig).toHaveBeenCalledWith({
         defaultModel: 'k2',
         defaultThinking: false,
-        thinking: { effort: 'off' },
+        thinking: { effort: 'off', mode: 'off' },
       });
     });
     expect(session.setModel).not.toHaveBeenCalled();
@@ -5301,7 +5301,7 @@ command = "vim"
       expect(setConfig).toHaveBeenCalledWith({
         defaultModel: 'k2',
         defaultThinking: true,
-        thinking: { effort: 'high' },
+        thinking: { effort: 'high', mode: 'on' },
       });
     });
     expect(driver.state.appState.thinkingLevel).toBe('high');