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March 29, 20263 min readAI Toolkit Plus Team

Gemini CLI Joins the AI Agent Race: How to Set Up Configs Alongside Claude Code, Cursor, and Copilot

Google's Gemini CLI is the newest AI coding agent. Here's how to configure it for your codebase — and keep it in sync with your other AI tools.

geminigoogleai-agentsconfigurationcomparison

Google's open-source Gemini CLI dropped in early 2026 and it's gaining traction fast. Powered by Gemini 3.1 Pro — which offers arguably the best price-to-performance ratio of any frontier model at $2/$12 per million tokens — it's become a serious contender for developer workflows.

But there's a catch: another agent means another config file to maintain. If you're already running Claude Code, Cursor, and Copilot, adding Gemini means you now have four different instruction files describing the same project.

Here's how to set up Gemini CLI properly — and how to keep all your agents in sync.

What Gemini CLI Expects

Gemini CLI reads a GEMINI.md file at your project root. The format is similar to Claude Code's CLAUDE.md: a markdown file with project context, conventions, and instructions. Gemini uses this to understand your codebase before making changes.

Key sections:

  • Project Overview — Languages, frameworks, entry points
  • Conventions — Language-specific coding standards
  • Testing — How to run tests, what frameworks are used
  • Git Workflow — Commit conventions, branch strategy

The Multi-Agent Config Problem

Here's what a typical multi-agent repo looks like:

my-project/
├── CLAUDE.md              # Claude Code
├── .cursorrules           # Cursor
├── .github/
│   └── copilot-instructions.md  # GitHub Copilot
├── .windsurfrules         # Windsurf
├── AGENTS.md              # OpenAI Codex
└── GEMINI.md              # Gemini CLI  ← NEW

Six files. Same project. If you update one manually, the others fall out of sync. Your Claude Code thinks you use Jest. Your Gemini CLI knows you switched to Vitest. Cursor still references the Express server you replaced with Fastify two months ago.

One Command, All Agents

AI Toolkit Plus now generates GEMINI.md alongside every other agent config:

bash
aitoolkitplus init --all

This analyzes your codebase once and generates all six configs simultaneously. Every agent gets the same project context — same languages, same frameworks, same conventions.

Gemini-Specific Output

The generated GEMINI.md includes:

markdown
# GEMINI.md

## Project Overview
This project uses **TypeScript, Go** with **Next.js, React, Tailwind CSS**.

## Tech Stack
| Category | Details |
|----------|---------|
| Languages | TypeScript, Go |
| Frameworks | Next.js, React, Tailwind CSS |
| Package Managers | pnpm, go modules |
| Testing | Vitest, go test |

## Conventions
### TypeScript
- Use strict TypeScript (`strict: true` in tsconfig)
- Prefer `const` over `let`; avoid `var` and `any`
...

Gemini CLI vs The Field

How does Gemini CLI compare to the other agents?

| Agent | Best For | Config File | Model | |-------|----------|-------------|-------| | Claude Code | Complex refactors, multi-file | CLAUDE.md | Opus 4.6 | | Cursor | Inline editing, rapid iteration | .cursorrules | Multiple | | Copilot | GitHub integration, completion | copilot-instructions.md | GPT-4o | | Windsurf | IDE-native agentic flows | .windsurfrules | Multiple | | Codex | Background batch tasks | AGENTS.md | GPT-5.3 Codex | | Gemini CLI | Cost-effective terminal agent | GEMINI.md | Gemini 3.1 Pro |

Gemini CLI's sweet spot is cost-sensitive workflows where you want a terminal-native agent but can't justify Claude Code's token costs for every task. At $2 per million input tokens, it's 10x cheaper than Opus for routine tasks.

Getting Started

bash
# Generate Gemini config alongside everything else
aitoolkitplus init --agent gemini

# Or generate all agents at once
aitoolkitplus init --all

# With production-readiness directives
aitoolkitplus init --agent gemini --12factor

The generated config automatically adapts to your detected tech stack. No manual editing required.

Keeping Configs Fresh

The update command re-analyzes your codebase and regenerates all configs:

bash
# Save your preferences once
aitoolkitplus init --all --save-config

# Whenever your codebase changes, just run:
aitoolkitplus update

Your Gemini CLI config stays in sync with your Claude Code, Cursor, and Copilot configs automatically.

AI Toolkit Plus generates configuration files for Claude Code, Cursor, Copilot, Windsurf, Codex, and Gemini CLI from a single command. Learn more.