Google's Gemini 3 Models Combine Web Search with Custom Tools

Google's Gemini 3 models now allow their google_search tool to be combined with custom function tools, a capability that was not available in previous Gemini 2.x models[12][13]. This integration, confirmed by Google documentation as of October 2026, means developers can blend real-time web data with tailored functionalities[13][14].

This development matters because it broadens the scope for developers to create more dynamic and factually accurate AI applications. By combining web search with custom functions, applications can access up-to-date information while performing specialized tasks, enhancing reliability and utility for users[14].

What the records show

Previous documentation indicated that Gemini 2.x models had a limitation preventing the google_search tool from being combined with custom function tools in a single request[11][12]. The adk.dev documentation noted that the google_search tool could only be used by itself within an agent instance[11].

However, this changed with Gemini 3 models. github.com stated on August 24, 2025, that "Gemini 3 added" this capability, overcoming the prior API limitation[12]. By October 13, 2026, google.dev explicitly confirmed that "Gemini 3 models also support combining these built-in tools with custom tools (function calling)"[13].

The timeline

Prior to Gemini 3, the architecture of Gemini 2.x models restricted the google_search tool to operate in isolation from custom functions[11][12]. The introduction of Gemini 3 models marked the point when this restriction was lifted[12][13]. As of October 13, 2026, official sources confirm that Gemini 3 models fully support the combination of built-in tools, including google_search, with custom tools[13].

What changed and for whom

For developers and users of Gemini models, the ability to combine google_search with custom tools represents an advancement. Developers can now design applications that perform real-time web searches and execute specific custom functions simultaneously within a single request[13][14]. This removes a previous hurdle that required separate calls or complex orchestration to achieve similar results, which was a challenge for Gemini 2.x users[11][12]. The new functionality means Gemini models can provide more accurate and up-to-date answers by leveraging current web content, while also performing specialized tasks defined by custom code[14].

What the subject has said publicly

Google's developer documentation, including google.dev, has affirmed that Gemini 3 models facilitate the combination of built-in tools like Google Search with custom tools[13]. This documentation, updated as recently as October 13, 2026, highlights the expanded capabilities for developers[13]. google.com outlined on October 14, 2026, the benefits of Grounding with Google Search, emphasizing its role in increasing factual accuracy, accessing real-time information, and providing verifiable sources[14]. Public statements from github.com on August 24, 2025, also acknowledged that Gemini 3 specifically addressed the limitation seen in Gemini 2.x models regarding tool combination[12].

What we could not confirm

We could not confirm the exact date in 2025 when Gemini 3 models were first released to the public or developers with this specific tool combination capability. The evidence indicates it was introduced sometime after August 24, 2025, but does not provide a precise launch date[12].