GoogleSearchTool rejects valid `-latest` model aliases (e.g., gemini-flash-latest)

[koverholt]

🔴 Required Information

Describe the Bug:

The GoogleSearchTool checks model.startsWith("gemini-2") || model.startsWith("gemini-3"), which rejects all -latest model aliases (gemini-flash-latest, gemini-pro-latest, gemini-flash-lite-latest). These are officially documented aliases: https://ai.google.dev/gemini-api/docs/models#latest

Steps to Reproduce:

1. Add com.google.adk:google-adk:1.2.0
2. Run the repro below
3. Observe: gemini-2.5-flash passes, gemini-flash-latest throws

Expected Behavior:

GoogleSearchTool accepts all valid Gemini model aliases.

Observed Behavior:

IllegalArgumentException: Google search tool is not supported for model gemini-flash-latest

Environment Details:

• ADK Library Version: 1.2.0
• OS: macOS
• Java: OpenJDK 17

Model Information:

• gemini-flash-latest

---

🟡 Optional Information

Regression:
Did this work in a previous version of ADK? (Yes/No) If so, which one?

• Introduced in v0.7.0 (PR feat: drop gemini-1 support in GoogleSearchTool #893)

Minimal Reproduction Code:

import com.google.adk.tools.GoogleSearchTool;
import com.google.adk.models.LlmRequest;
import com.google.genai.types.GenerateContentConfig;
public class ReproBug {
    public static void main(String[] args) {
        var tool = new GoogleSearchTool();
        var working = LlmRequest.builder()
            .config(GenerateContentConfig.builder().build())
            .model("gemini-2.5-flash").build();
        tool.processLlmRequest(working.toBuilder(), null).blockingAwait();
        System.out.println("PASS: gemini-2.5-flash");
        try {
            var broken = LlmRequest.builder()
                .config(GenerateContentConfig.builder().build())
                .model("gemini-flash-latest").build();
            tool.processLlmRequest(broken.toBuilder(), null).blockingAwait();
            System.out.println("PASS: gemini-flash-latest");
        } catch (Exception e) {
            System.out.println("FAIL: " + e.getMessage());
        }
    }
}

How often has this issue occurred?:

• Always (100%)