Try the new Built-in tools and Function calling combination feature, and Grounding with Google Maps, now supported for Gemini 3 models.

Combine built-in tools and function calling

Gemini allows the combination of built-in tools, such as google_search, and function calling (also known as custom tools) in a single generation by preserving and exposing the context history of tool calls. Built-in and custom tool combinations allow for complex, agentic workflows where, for example, the model can ground itself in real-time web data before calling your specific business logic.

Here's an example that enables built-in and custom tool combinations with google_search and a custom function getWeather:

Python

from google import genai
from google.genai import types

client = genai.Client()

getWeather = {
    "name": "getWeather",
    "description": "Gets the weather for a requested city.",
    "parameters": {
        "type": "object",
        "properties": {
            "city": {
                "type": "string",
                "description": "The city and state, e.g. Utqiaġvik, Alaska",
            },
        },
        "required": ["city"],
    },
}

# Turn 1: Initial request with Google Search (built-in) and getWeather (custom) tools enabled
response = client.models.generate_content(
    model="gemini-3-flash-preview",
    contents="What is the northernmost city in the United States? What's the weather like there today?",
    config=types.GenerateContentConfig(
      tools=[
        types.Tool(
          google_search=types.ToolGoogleSearch(),  # Built-in tool
          function_declarations=[getWeather]       # Custom tool
        ),
      ],
      include_server_side_tool_invocations=True
    ),
)

for part in response.candidates[0].content.parts:
    if part.tool_call:
        print(f"Tool call: {part.tool_call.tool_type} (ID: {part.tool_call.id})")
    if part.tool_response:
        print(f"Tool response: {part.tool_response.tool_type} (ID: {part.tool_response.id})")
    if part.function_call:
        print(f"Function call: {part.function_call.name} (ID: {part.function_call.id})")

# Turn 2: Manually build history to circulate both tool and function context
history = [
    types.Content(
        role="user",
        parts=[types.Part(text="What is the northernmost city in the United States? What's the weather like there today?")]
    ),
    # Response from Turn 1 includes tool_call, tool_response, and thought_signatures
    response.candidates[0].content,
    # Return the function_response
    types.Content(
        role="user",
        parts=[types.Part(
            function_response=types.FunctionResponse(
                name="getWeather",
                response={"response": "Very cold. 22 degrees Fahrenheit."},
                id=response.candidates[0].content.parts[2].function_call.id # Match the ID from the function_call
            )
        )]
    )
]

response_2 = client.models.generate_content(
    model="gemini-3-flash-preview",
    contents=history,
    config=types.GenerateContentConfig(
      tools=[
        types.Tool(
          google_search=types.ToolGoogleSearch(),
          function_declarations=[getWeather]
        ),
      ],
      # This flag needs to be enabled for built-in tool context circulation and tool combination
      include_server_side_tool_invocations=True
    ),
)

for part in response_2.candidates[0].content.parts:
    if part.text:
        print(part.text)

Javascript

import { GoogleGenAI } from '@google/genai';

const client = new GoogleGenAI({});

const getWeather = {
    name: "getWeather",
    description: "Get the weather in a given location",
    parameters: {
        type: "OBJECT",
        properties: {
            location: {
                type: "STRING",
                description: "The city and state, e.g. San Francisco, CA"
            }
        },
        required: ["location"]
    }
};

async function run() {
    const model = client.getGenerativeModel({
        model: "gemini-3-flash-preview",
    });

    const tools = [
      { googleSearch: {} },
      { functionDeclarations: [getWeather] }
    ];
    // This flag needs to be enabled for built-in tool context circulation and tool combination
    const toolConfig = { includeServerSideToolInvocations: true };

    // Turn 1: Initial request with Google Search (built-in) and getWeather (custom) tools enabled
    const result1 = await model.generateContent({
        contents: [{role: "user", parts: [{text: "What is the northernmost city in the United States? What's the weather like there today?"}]}],
        tools: tools,
        toolConfig: toolConfig,
    });

    const response1 = result1.response;

    for (const part of response1.candidates[0].content.parts) {
        if (part.toolCall) {
            console.log(`Tool call: ${part.toolCall.toolType} (ID: ${part.toolCall.id})`);
        }
        if (part.toolResponse) {
            console.log(`Tool response: ${part.toolResponse.toolType} (ID: ${part.toolResponse.id})`);
        }
        if (part.functionCall) {
            console.log(`Function call: ${part.functionCall.name} (ID: ${part.functionCall.id})`);
        }
    }

    const functionCallId = response1.candidates[0].content.parts.find(p => p.functionCall)?.functionCall?.id;

    // Turn 2: Manually build history to circulate both tool and function context
    const history = [
        {
            role: "user",
            parts:[{text: "What is the northernmost city in the United States? What's the weather like there today?"}]
        },
        // Response from Turn 1 includes tool_call, tool_response, and thought_signatures
        response1.candidates[0].content,
        // Return the function_response
        {
            role: "user",
            parts: [{
                functionResponse: {
                    name: "getWeather",
                    response: {response: "Very cold. 22 degrees Fahrenheit."},
                    id: functionCallId // Match the ID from the function_call
                }
            }]
        }
    ];

    const result2 = await model.generateContent({
        contents: history,
        tools: tools,
        toolConfig: toolConfig,
    });

    for (const part of result2.response.candidates[0].content.parts) {
        if (part.text) {
            console.log(part.text);
        }
    }
}

run();

Go

package main

import (
    "context"
    "fmt"
    "log"
    "os"

    "github.com/google/generative-ai-go/genai"
    "google.golang.org/api/option"
)

func main() {
    ctx := context.Background()
    client, err := genai.NewClient(ctx, option.WithAPIKey(os.Getenv("GEMINI_API_KEY")))
    if err != nil {
        log.Exit(err)
    }
    defer client.Close()

    getWeather := &genai.FunctionDeclaration{
        Name:        "getWeather",
        Description: "Get the weather in a given location",
        Parameters: &genai.Schema{
            Type: genai.Object,
            Properties: map[string]*genai.Schema{
                "location": {
                    Type:        genai.String,
                    Description: "The city and state, e.g. San Francisco, CA",
                },
            },
            Required: []string{"location"},
        },
    }

    model := client.GenerativeModel("gemini-3-flash-preview")
    model.Tools = []*genai.Tool{
        {GoogleSearch: &genai.GoogleSearch{}}, // Built-in tool
        {FunctionDeclarations: []*genai.FunctionDeclaration{getWeather}}, // Custom tool
    }
    ist := true
    model.ToolConfig = &genai.ToolConfig{
        IncludeServerSideToolInvocations: &ist, // This flag needs to be enabled for built-in tool context circulation and tool combination
    }

    chat := model.StartChat()

    // Turn 1: Initial request with Google Search (built-in) and getWeather (custom) tools enabled
    prompt := genai.Text("What is the northernmost city in the United States? What's the weather like there today?")
    resp1, err := chat.SendMessage(ctx, prompt)
    if err != nil {
        log.Exitf("SendMessage failed: %v", err)
    }

    if resp1 == nil || len(resp1.Candidates) == 0 || resp1.Candidates[0].Content == nil {
        log.Exit("empty response from model")
    }

    var functionCallID string
    for _, part := range resp1.Candidates[0].Content.Parts {
        switch p := part.(type) {
        case genai.FunctionCall:
            fmt.Printf("Function call: %s (ID: %s)\n", p.Name, p.ID)
            if p.Name == "getWeather" {
                functionCallID = p.ID
            }
        case genai.ToolCallPart:
            fmt.Printf("Tool call: %s (ID: %s)\n", p.ToolType, p.ID)
        case genai.ToolResponsePart:
            fmt.Printf("Tool response: %s (ID: %s)\n", p.ToolType, p.ID)
        }
    }

    if functionCallID == "" {
        log.Exit("no getWeather function call in response")
    }

    // Turn 2: Provide function result back to model.
    // Chat history automatically includes tool_call, tool_response, and thought_signatures from Turn 1.
    fr := genai.FunctionResponse{
        Name: "getWeather",
        ID:   functionCallID,
        Response: map[string]any{
            "response": "Very cold. 22 degrees Fahrenheit.",
        },
    }

    resp2, err := chat.SendMessage(ctx, fr)
    if err != nil {
        log.Exitf("SendMessage for turn 2 failed: %v", err)
    }

    if resp2 == nil || len(resp2.Candidates) == 0 || resp2.Candidates[0].Content == nil {
        log.Exit("empty response from model in turn 2")
    }

    for _, part := range resp2.Candidates[0].Content.Parts {
        if txt, ok := part.(genai.Text); ok {
            fmt.Println(string(txt))
        }
    }
}

REST

# Turn 1: Initial request with Google Search (built-in) and getWeather (custom) tools enabled
curl -X POST "https://generativelanguage.googleapis.com/v1beta/models/gemini-3-flash-preview:generateContent" \
-H "Content-Type: application/json" \
-H "x-goog-api-key: $GEMINI_API_KEY" \
-d '{
  "contents": [{
    "role": "user",
    "parts": [{
      "text": "What is the northernmost city in the United States? What'\''s the weather like there today?"
    }]
  }],
  "tools": [{
    "googleSearch": {}
  }, {
    "functionDeclarations": [{
      "name": "getWeather",
      "description": "Get the weather in a given location",
      "parameters": {
          "type": "OBJECT",
          "properties": {
              "location": {
                  "type": "STRING",
                  "description": "The city and state, e.g. San Francisco, CA"
              }
          },
          "required": ["location"]
      }
    }]
  }],
  "toolConfig": {
    "includeServerSideToolInvocations": true
  }
}'

# Turn 2: Manually build history to circulate both tool and function context
# The following request assumes you have captured candidates[0].content from Turn 1 response,
# and extracted function_call.id for getWeather.
# Replace FUNCTION_CALL_ID and insert candidate content from turn 1.
curl -X POST "https://generativelanguage.googleapis.com/v1beta/models/gemini-3-flash-preview:generateContent" \
-H "Content-Type: application/json" \
-H "x-goog-api-key: $GEMINI_API_KEY" \
-d '{
  "contents": [
    {
      "role": "user",
      "parts": [{"text": "What is the northernmost city in the United States? What'\''s the weather like there today?"}]
    },
    YOUR_CANDIDATE_CONTENT_FROM_TURN_1_RESPONSE,
    {
      "role": "user",
      "parts": [{
        "functionResponse": {
          "name": "getWeather",
          "id": "FUNCTION_CALL_ID",
          "response": {"response": "Very cold. 22 degrees Fahrenheit."}
        }
      }]
    }
  ],
  "tools": [{
    "googleSearch": {}
  }, {
    "functionDeclarations": [{
      "name": "getWeather",
      "description": "Get the weather in a given location",
      "parameters": {
          "type": "OBJECT",
          "properties": {
              "location": {
                  "type": "STRING",
                  "description": "The city and state, e.g. San Francisco, CA"
              }
          },
          "required": ["location"]
      }
    }]
  }],
  "toolConfig": {
    "includeServerSideToolInvocations": true
  }
}'

How it works

Gemini 3 models use tool context circulation to enable built-in and custom tool combinations. Tool context circulation makes it possible to preserve and expose the context of built-in tools and share it with custom tools in the same call from turn to turn.

Enable tool combination

You must set the include_server_side_tool_invocations flag to true to enable tool context circulation.
Include the function_declarations, along with the built-in tools you want to use, to trigger the combination behavior.
- If you don't include function_declarations, tool context circulation will still act on the included built-in tools, as long as the flag is set.

API returns parts

In a single response, the API returns the toolCall and toolResponse parts for the built-in tool call. For the function (custom tool) call, the API returns the functionCall call part, to which the user provides the functionResponse part in the next turn.

toolCall and toolResponse: The API returns these parts to preserve the context of which tools are run on the server side, and the result of their execution, for the next turn.
functionCall and functionResponse: The API sends the function call to the user to fill out, and the user sends the result back in the function response (these parts are standard to all function calling in the Gemini API, not unique to the tool combination feature).
(Code execution tool only) executableCode and codeExecutionResult: When using the Code Execution tool, instead of functionCall and functionResponse, the API returns executableCode (the code generated by the model that's meant to be executed) and codeExecutionResult (the result of the executable code).

You must return all parts, including all the fields they contain, back to the model on each turn to maintain context and enable tool combinations.

Critical fields in returned parts

Certain parts returned by the API will include id, tool_type, and thought_signature fields. These fields are critical to maintaining tool context (and therefore critical to tool combinations); you need to return all parts as given in the response in your subsequent requests.

id: A unique identifier that maps a call to its response. id is set on all function call responses, regardless of tool context circulation. You must provide the same id in the function response that the API provides in the function call. Built-in tools automatically share the id between the tool call and tool response.
- Found in all tool-related parts: toolCall, toolResponse, functionCall, functionResponse, executableCode, codeExecutionResult
tool_type: Identifies the specific tool being used; the literal built-in tool or (e.g. URL_CONTEXT) or function (e.g. getWeather) name.
- Found in toolCall and toolResponse parts.
thought_signature: The actual encrypted context embedded in each part returned by the API. Context can't be reconstructed without thought signatures; if you don't return the thought signatures for all parts in every turn, the model will error out.
- Found in all parts.

Tool-specific data

Some built-in tools return user-visible data arguments specific to the tool type.

Tool	User visible tool call args (if any)	User visible tool response (if any)
GOOGLE_SEARCH	`queries`	`search_suggestions`
GOOGLE_MAPS	`queries`	`places` `google_maps_widget_context_token`
URL_CONTEXT	`urls` URLs to be browsed	`urls_metadata` `retrieved_url`: URLs browsed `url_retrieval_status`: Browse status
FILE_SEARCH	None	None

Example tool combination request structure

The following request structure shows the request structure of the prompt: "What is the northernmost city in the United States? What's the weather like there today?". It combines three tools: the built-in Gemini tools google_search and code_execution, and a custom function get_weather.

{
  "model": "models/gemini-3-flash-preview",
  "contents": [{
    "parts": [{
      "text": "What is the northernmost city in the United States? What's the weather like there today?"
    }],
    "role": "user"
  }, {
    "parts": [{
      "thoughtSignature": "...",
      "toolCall": {
        "toolType": "GOOGLE_SEARCH_WEB",
        "args": {
          "queries": ["northernmost city in the United States"]
        },
        "id": "a7b3k9p2"
      }
    }, {
      "thoughtSignature": "...",
      "toolResponse": {
        "toolType": "GOOGLE_SEARCH_WEB",
        "response": {
          "search_suggestions": "..."
        },
        "id": "a7b3k9p2"
      }
    }, {
      "functionCall": {
        "name": "getWeather",
        "args": {
          "city": "Utqiaġvik, Alaska"
        },
        "id": "m4q8z1v6"
      },
      "thoughtSignature": "..."
    }],
    "role": "model"
  }, {
    "parts": [{
      "functionResponse": {
        "name": "getWeather",
        "response": {
          "response": "Very cold. 22 degrees Fahrenheit."
        },
        "id": "m4q8z1v6"
      }
    }],
    "role": "user"
  }],
  "tools": [{
    "functionDeclarations": [{
      "name": "getWeather"
    }]
  }, {
    "googleSearch": {
    }
  }, {
    "codeExecution": {
    }
  }],
  "toolConfig": {
    "includeServerSideToolInvocations": true
  }
}

Tokens and pricing

Note that toolCall and toolResponse parts in requests are counted towards prompt_token_count. Since these intermediate tool steps are now visible and returned to you, they are part of the conversation history. This is only the case for requests, not responses.

The Google Search tool is an exception to this rule. Google Search already applies its own pricing model at the query level, so tokens are not double-charged (see the Pricing page).

Read the Tokens page for more information.

Limitations

Default to VALIDATED mode (AUTO mode is not supported) when include_server_side_tool_invocations flag is enabled
Built-in tools like google_search rely on location and current time information, so if your system_instruction or function_declaration.description has conflicting location and time information, the tool combination feature might not work well.

Supported tools

Standard tool context circulation applies to server-side (built-in) tools. Code Execution is also a server-side tool, but has its own built-in solution to context circulation. Computer Use and function calling are client-side tools, and also have built-in solutions to context circulation.

Tool	Execution side	Context Circulation Support
Google Search	Server-side	Supported
Google Maps	Server-side	Supported
URL Context	Server-side	Supported
File Search	Server-side	Supported
Code Execution	Server-side	Supported (built in, uses `executableCode` and `codeExecutionResult` parts)
Computer Use	Client-side	Supported (built in, uses `functionCall` and `functionResponse` parts)
Custom functions	Client-side	Supported (built in, uses `functionCall` and `functionResponse` parts)

What's next

Learn more about Function calling in the Gemini API.
Explore the supported tools: