From e6897df911ef2a1adaabfce1cdd3e15521368395 Mon Sep 17 00:00:00 2001
From: Amaad Martin <amaadmartin@google.com>
Date: Mon, 3 Aug 2026 22:21:20 -0700
Subject: [PATCH] Fix: match only gemini-1.<digit> in isGemini1Model
 (adk-python parity)

isGemini1Model used a bare `startsWith('gemini-1')` prefix test with no
digit boundary, so it accepted any id whose version field merely begins
with the character `1`. A future `gemini-10.0-pro` would be routed down
the legacy Gemini 1.x paths in GoogleSearchTool, VertexAiSearchTool,
applyGoogleMapsGrounding and applyEnterpriseWebSearch, and would also be
classified as both Gemini 1.x and Gemini 2.0+ at the same time.

Replace the prefix test with the `^gemini-1\.\d+` regex adk-python's
is_gemini_1_model already uses, hoisted to a module-level non-global
constant so `.test()` stays stateless. This makes the existing doc
comment ("using regex patterns") honest and restores mutual exclusivity
with isGemini2OrAbove.

Behaviour is unchanged for every real Gemini 1.x id; only gemini-10.0-pro,
gemini-1, gemini-1-pro, gemini-1. and gemini-1x-foo flip to false.
---
 core/src/utils/model_name.ts       |  4 +-
 core/test/utils/model_name_test.ts | 73 ++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/core/src/utils/model_name.ts b/core/src/utils/model_name.ts
index 6851eaba4..ff1c29a56 100644
--- a/core/src/utils/model_name.ts
+++ b/core/src/utils/model_name.ts
@@ -9,6 +9,8 @@ import {getBooleanEnvVar} from './env_aware_utils.js';
 const MODEL_NAME_PATTERN =
   '^projects/[^/]+/locations/[^/]+/publishers/[^/]+/models/(.+)$';
 
+const GEMINI_1_MODEL_PATTERN = /^gemini-1\.\d+/;
+
 /**
  * Extract the actual model name from either simple or path-based format.
  *
@@ -68,7 +70,7 @@ function parseVersion(versionString: string): ParsedVersion {
 export function isGemini1Model(modelString: string): boolean {
   const modelName = extractModelName(modelString);
 
-  return modelName.startsWith('gemini-1');
+  return GEMINI_1_MODEL_PATTERN.test(modelName);
 }
 
 /**
diff --git a/core/test/utils/model_name_test.ts b/core/test/utils/model_name_test.ts
index caabe4022..792041b09 100644
--- a/core/test/utils/model_name_test.ts
+++ b/core/test/utils/model_name_test.ts
@@ -6,6 +6,79 @@
 
 import {isGemini2OrAbove, isGemini3xFlashLive} from '@google/adk';
 import {describe, expect, it} from 'vitest';
+import {isGemini1Model, isGeminiModel} from '../../src/utils/model_name.js';
+
+describe('isGemini1Model', () => {
+  const gemini1Models = [
+    'gemini-1.5-flash',
+    'gemini-1.0-pro',
+    'gemini-1.5-pro-preview',
+    'gemini-1.9-experimental',
+    'projects/265104255505/locations/us-central1/publishers/google/models/gemini-1.5-flash',
+    'projects/12345/locations/us-east1/publishers/google/models/gemini-1.0-pro-preview',
+  ];
+
+  describe('valid models', () => {
+    for (const model of gemini1Models) {
+      it(`should return true for model: ${model}`, () => {
+        expect(isGemini1Model(model)).toBe(true);
+      });
+    }
+  });
+
+  describe('invalid models', () => {
+    const invalidModels = [
+      // A double-digit major must not be read as Gemini 1.x.
+      'gemini-10.0-pro',
+      // The dotted minor version is mandatory.
+      'gemini-1',
+      'gemini-1-pro',
+      'gemini-1.',
+      'gemini-1x-foo',
+      'gemini-2.5-flash',
+      'claude-3-sonnet',
+      // Present but not anchored at the start of the model name.
+      'my-gemini-1.5-model',
+      '',
+      'projects/265104255505/locations/us-central1/publishers/google/models/gemini-2.5-flash',
+    ];
+
+    for (const model of invalidModels) {
+      it(`should return false for model: ${model || '<empty string>'}`, () => {
+        expect(isGemini1Model(model)).toBe(false);
+      });
+    }
+  });
+
+  describe('classification invariants', () => {
+    const allModels = [
+      ...gemini1Models,
+      'gemini-10.0-pro',
+      'gemini-1',
+      'gemini-1-pro',
+      'gemini-2.5-flash',
+      'gemini-3-pro-preview',
+      'claude-3-sonnet',
+      '',
+    ];
+
+    it('should never classify a model as both Gemini 1.x and Gemini 2.0+', () => {
+      expect(
+        allModels.filter(
+          (model) => isGemini1Model(model) && isGemini2OrAbove(model),
+        ),
+      ).toEqual([]);
+    });
+
+    it('should classify every Gemini 1.x model as a Gemini model', () => {
+      expect(
+        allModels.filter(
+          (model) => isGemini1Model(model) && !isGeminiModel(model),
+        ),
+      ).toEqual([]);
+    });
+  });
+});
 
 describe('isGemini2OrAbove', () => {
   describe('valid models', () => {