diff --git a/docs/get-started/configuration.md b/docs/get-started/configuration.md
index 4bc55083bd..02df8c67a0 100644
--- a/docs/get-started/configuration.md
+++ b/docs/get-started/configuration.md
@@ -827,7 +827,7 @@ their corresponding top-level category object in your `settings.json` file.
 
 - **`experimental.codebaseInvestigatorSettings.model`** (string):
   - **Description:** The model to use for the Codebase Investigator agent.
-  - **Default:** `"gemini-2.5-pro"`
+  - **Default:** `"pro"`
   - **Requires restart:** Yes
 
 #### `hooks`
diff --git a/packages/core/src/config/config.test.ts b/packages/core/src/config/config.test.ts
index 79418ad19b..90247b4441 100644
--- a/packages/core/src/config/config.test.ts
+++ b/packages/core/src/config/config.test.ts
@@ -34,7 +34,6 @@ import { logRipgrepFallback } from '../telemetry/loggers.js';
 import { RipgrepFallbackEvent } from '../telemetry/types.js';
 import { ToolRegistry } from '../tools/tool-registry.js';
 import { DEFAULT_MODEL_CONFIGS } from './defaultModelConfigs.js';
-import { GEMINI_MODEL_ALIAS_PRO } from './models.js';
 
 vi.mock('fs', async (importOriginal) => {
   const actual = await importOriginal<typeof import('fs')>();
@@ -889,11 +888,9 @@ describe('Server Config (config.ts)', () => {
       expect(SubagentToolWrapperMock).not.toHaveBeenCalled();
     });
 
-    it('should default codebase investigator model to PRO alias', () => {
+    it('should not set default codebase investigator model in config (defaults in registry)', () => {
       const config = new Config(baseParams);
-      expect(config.getCodebaseInvestigatorSettings()?.model).toBe(
-        GEMINI_MODEL_ALIAS_PRO,
-      );
+      expect(config.getCodebaseInvestigatorSettings()?.model).toBeUndefined();
     });
 
     describe('with minified tool class names', () => {
diff --git a/packages/core/src/config/config.ts b/packages/core/src/config/config.ts
index 38b224820a..678af20cd0 100644
--- a/packages/core/src/config/config.ts
+++ b/packages/core/src/config/config.ts
@@ -49,7 +49,6 @@ import {
   DEFAULT_GEMINI_EMBEDDING_MODEL,
   DEFAULT_GEMINI_FLASH_MODEL,
   DEFAULT_THINKING_MODE,
-  GEMINI_MODEL_ALIAS_PRO,
 } from './models.js';
 import { shouldAttemptBrowserLaunch } from '../utils/browser.js';
 import type { MCPOAuthConfig } from '../mcp/oauth-provider.js';
@@ -573,8 +572,7 @@ export class Config {
       thinkingBudget:
         params.codebaseInvestigatorSettings?.thinkingBudget ??
         DEFAULT_THINKING_MODE,
-      model:
-        params.codebaseInvestigatorSettings?.model ?? GEMINI_MODEL_ALIAS_PRO,
+      model: params.codebaseInvestigatorSettings?.model,
     };
     this.continueOnFailedApiCall = params.continueOnFailedApiCall ?? true;
     this.enableShellOutputEfficiency =