gemini-api-dev

name	gemini-api-dev
description	Direct Gemini API development with google-genai (Python) and @google/genai (TypeScript). Use when building multimodal applications, function calling, structured output, context caching, embeddings, or code execution with Gemini models — without the ADK framework overhead.
allowed-tools	Bash, Read, Write, Edit, WebFetch
metadata	{"triggers":"Gemini API, google-genai, @google/genai, multimodal, Gemini embeddings, context caching, code execution sandbox, Gemini function calling, Gemini structured output, direct Gemini, gemini-3.1","related-skills":"google-adk, agentic-ai-dev, python-dev, nestjs-api","domain":"backend","role":"specialist","scope":"implementation","output-format":"code"}
last-reviewed	2026-03-15

Iron Law

ALWAYS FETCH CURRENT API DOCS BEFORE WRITING CODE — fetch https://ai.google.dev/gemini-api/docs/llms.txt first, then the specific capability page. Never generate Gemini API calls from memory; the API evolves rapidly.

Gemini API Development — Direct API (google-genai / @google/genai)

When to Use This Skill vs google-adk

Use Case	This Skill	google-adk skill
Direct model API calls	✅	❌
Multimodal (image/audio/video)	✅	Partial
Embeddings API	✅	❌
Context caching	✅	❌
Code execution sandbox	✅	❌
Building structured AI agents	❌	✅
Session management / memory	❌	✅
Multi-agent orchestration	❌	✅

Current Models (as of 2026-03-15)

• gemini-3.1-flash — 1M tokens, fast, balanced, multimodal. Default for most tasks.
• gemini-3.1-pro — 1M tokens, complex reasoning, coding, research
• gemini-3.1-pro-image — Image generation and editing

Legacy models are deprecated: gemini-2.5-*, gemini-2.0-*, gemini-1.5-* — do not use.

SDKs

• Python: google-genai — uv add google-genai
• TypeScript/NestJS: @google/genai — npm install @google/genai

Legacy SDKs are deprecated: google-generativeai (Python) and @google/generative-ai (JS) — do not use.

Quick Start

Python

from google import genai

client = genai.Client()  # uses GOOGLE_API_KEY env var
response = client.models.generate_content(
    model="gemini-3.1-flash",
    contents="Explain quantum computing"
)
print(response.text)

TypeScript (NestJS)

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

const ai = new GoogleGenAI({});  // uses GOOGLE_API_KEY env var
const response = await ai.models.generateContent({
  model: "gemini-3.1-flash",
  contents: "Explain quantum computing"
});
console.log(response.text);

Key Capabilities

Capability	When to Use	Doc Page
Text generation	Chat, completion, summarization	text-generation.md.txt
Multimodal	Process images, audio, video, documents	image-understanding.md.txt
Function calling	Let the model invoke your functions	function-calling.md.txt
Structured output	Generate valid JSON matching schema	structured-output.md.txt
Code execution	Run Python in sandboxed environment	fetch from llms.txt
Context caching	Cache large contexts for cost efficiency	fetch from llms.txt
Embeddings	Semantic search, similarity	embeddings.md.txt

Documentation Sources

Always fetch before writing code — the Gemini API evolves rapidly; never rely on memory.

Source	URL	Purpose
Doc index	https://ai.google.dev/gemini-api/docs/llms.txt	Discover all available doc pages
Models	https://ai.google.dev/gemini-api/docs/models.md.txt	Current model IDs and capabilities
Function calling	https://ai.google.dev/gemini-api/docs/function-calling.md.txt	Tool use patterns
Structured output	https://ai.google.dev/gemini-api/docs/structured-output.md.txt	JSON schema output
Embeddings	https://ai.google.dev/gemini-api/docs/embeddings.md.txt	Embedding API
Text generation	https://ai.google.dev/gemini-api/docs/text-generation.md.txt	Generation parameters
Image understanding	https://ai.google.dev/gemini-api/docs/image-understanding.md.txt	Multimodal inputs
SDK migration	https://ai.google.dev/gemini-api/docs/migrate.md.txt	Migrate from legacy SDKs
REST API spec	https://generativelanguage.googleapis.com/$discovery/rest?version=v1beta	Authoritative API schema

Common Commands

# Python setup
uv add google-genai

# TypeScript setup
npm install @google/genai

# Set API key (get from Google AI Studio: aistudio.google.com)
export GOOGLE_API_KEY=your_key_here

# Verify SDK version
python -c "import google.genai; print(google.genai.__version__)"
node -e "const {GoogleGenAI}=require('@google/genai'); console.log('ok')"

Error Handling

Fetch https://ai.google.dev/gemini-api/docs/error-codes.md.txt for current error code reference.

Rate limits (429): Implement exponential backoff — do not retry immediately. Invalid API key (401): Check GOOGLE_API_KEY env var — never hardcode keys. Model not found: Verify model ID against models.md.txt — model names change between releases. Payload too large: Check 2MB limit for inline data; use File API for larger inputs.

# Python — retry with backoff on rate limit
import time
from google.api_core import retry
from google import genai

client = genai.Client()

@retry.Retry(predicate=retry.if_transient_error)
def generate_with_retry(prompt: str) -> str:
    response = client.models.generate_content(
        model="gemini-3.1-flash",
        contents=prompt,
    )
    return response.text

Post-Code Review

After writing Gemini API integration code, dispatch:

• security-reviewer — API key handling, no keys in code, input sanitization before sending to model
• code-reviewer — general quality, error handling completeness