gemini-api-dev

# Gemini API Development Skill

## Overview

The Gemini API provides access to Google's most advanced AI models. Key capabilities include:

- **Text generation** - Chat, completion, summarization

- **Multimodal understanding** - Process images, audio, video, and documents

- **Function calling** - Let the model invoke your functions

- **Structured output** - Generate valid JSON matching your schema

- **Code execution** - Run Python code in a sandboxed environment

- **Context caching** - Cache large contexts for efficiency

- **Embeddings** - Generate text embeddings for semantic search

## Current Gemini Models

- gemini-3-pro-preview: 1M tokens, complex reasoning, coding, research

- gemini-3-flash-preview: 1M tokens, fast, balanced performance, multimodal

- gemini-3-pro-image-preview: 65k / 32k tokens, image generation and editing

[!IMPORTANT]

Models like gemini-2.5-\*, gemini-2.0-\*, gemini-1.5-\* are legacy and deprecated. Use the new models above. Your knowledge is outdated.

## SDKs

- **Python**: google-genai install with pip install google-genai

- **JavaScript/TypeScript**: @google/genai install with npm install @google/genai

- **Go**: google.golang.org/genai install with go get google.golang.org/genai

- **Java**:

  - groupId: com.google.genai, artifactId: google-genai

  - Latest version can be found here: https://central.sonatype.com/artifact/com.google.genai/google-genai/versions (let's call it LAST\_VERSION)

  - Install in build.gradle:

  ```

  implementation("com.google.genai:google-genai:${LAST_VERSION}")

  ```

  - Install Maven dependency in pom.xml:

  ```

  <dependency>

  <groupId>com.google.genai</groupId>

  <artifactId>google-genai</artifactId>

  <version>${LAST_VERSION}</version>

  </dependency>

  ```

[!WARNING]

Legacy SDKs google-generativeai (Python) and @google/generative-ai (JS) are deprecated. Migrate to the new SDKs above urgently by following the Migration Guide.

## Quick Start

### Python

from google import genai



client = genai.Client()

response = client.models.generate\_content(

    model="gemini-3-flash-preview",

    contents="Explain quantum computing"

)

print(response.text)

### JavaScript/TypeScript

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



const ai = new GoogleGenAI({});

const response = await ai.models.generateContent({

  model: "gemini-3-flash-preview",

  contents: "Explain quantum computing"

});

console.log(response.text);

### Go

package main



import (

 	"context"

 	"fmt"

 	"log"

 	"google.golang.org/genai"

)



func main() {

 	ctx := context.Background()

 	client, err := genai.NewClient(ctx, nil)

 	if err != nil {

 		log.Fatal(err)

 	}



 	resp, err := client.Models.GenerateContent(ctx, "gemini-3-flash-preview", genai.Text("Explain quantum computing"), nil)

 	if err != nil {

 		log.Fatal(err)

 	}



 	fmt.Println(resp.Text)

}

### Java

import com.google.genai.Client;

import com.google.genai.types.GenerateContentResponse;



public class GenerateTextFromTextInput {

  public static void main(String\[] args) {

    Client client = new Client();

    GenerateContentResponse response =

        client.models.generateContent(

            "gemini-3-flash-preview",

            "Explain quantum computing",

            null);



    System.out.println(response.text());

  }

}

## API spec (source of truth)

**Always use the latest REST API discovery spec as the source of truth for API definitions** (request/response schemas, parameters, methods). Fetch the spec when implementing or debugging API integration:

- **v1beta** (default): https://generativelanguage.googleapis.com/$discovery/rest?version=v1beta

  Use this unless the integration is explicitly pinned to v1. The official SDKs (google-genai, @google/genai, google.golang.org/genai) target v1beta.

- **v1**: https://generativelanguage.googleapis.com/$discovery/rest?version=v1

  Use only when the integration is specifically set to v1.

When in doubt, use v1beta. Refer to the spec for exact field names, types, and supported operations.

## How to use the Gemini API

For detailed API documentation, fetch from the official docs index:

**llms.txt URL**: https://ai.google.dev/gemini-api/docs/llms.txt

This index contains links to all documentation pages in .md.txt format. Use web fetch tools to:

1. Fetch llms.txt to discover available documentation pages

2. Fetch specific pages (e.g., https://ai.google.dev/gemini-api/docs/function-calling.md.txt)

### Key Documentation Pages

[!IMPORTANT]

Those are not all the documentation pages. Use the llms.txt index to discover available documentation pages

- [Models](https://ai.google.dev/gemini-api/docs/models.md.txt)

- [Google AI Studio quickstart](https://ai.google.dev/gemini-api/docs/ai-studio-quickstart.md.txt)

- [Nano Banana image generation](https://ai.google.dev/gemini-api/docs/image-generation.md.txt)

- [Function calling with the Gemini API](https://ai.google.dev/gemini-api/docs/function-calling.md.txt)

- [Structured outputs](https://ai.google.dev/gemini-api/docs/structured-output.md.txt)

- [Text generation](https://ai.google.dev/gemini-api/docs/text-generation.md.txt)

- [Image understanding](https://ai.google.dev/gemini-api/docs/image-understanding.md.txt)

- [Embeddings](https://ai.google.dev/gemini-api/docs/embeddings.md.txt)

- [Interactions API](https://ai.google.dev/gemini-api/docs/interactions.md.txt)

- [SDK migration guide](https://ai.google.dev/gemini-api/docs/migrate.md.txt)