Gemini CLI vs JetBrains AI / Junie

Gemini CLI vs JetBrains AI / JunieComparisonUpdated 2026-03-16

SUMMARY

Gemini CLI (CLI) uses markdown configuration while JetBrains AI / Junie (IDE) uses markdown. They differ on 4 of 11 compared features. Both tools provide AI-assisted development but take different approaches to project configuration.

FEATURE COMPARISON

Feature	Gemini CLI	JetBrains AI / Junie	Notes
Config format	markdown	markdown
Hierarchy support	✓	✗	Whether config files can be placed at multiple directory levels
Global config	✓	✗	User-wide configuration outside any project
Project config	✓	✓
Subdirectory scoping	✗	✗	Config files in subdirectories that apply only to that subtree
File inclusion / imports	✗	✗	Ability to include or reference other files from config
Ignore file	✗	.aiignore
IDE integration	CLI	✓
Schema / structure	Free-form (Markdown)	Free-form (Markdown)	Whether config uses structured schema or free-form content
Git committed	✓	✓	Whether primary config files are intended to be version-controlled
Encoding	UTF-8	UTF-8

FILE MAPPING

Purpose	Gemini CLI	JetBrains AI / Junie
Settings / configuration	.gemini/settings.json	.noai

SIDE-BY-SIDE CODE SAMPLES

Gemini CLI

GEMINI.md

markdown

# Project Context

## Stack
- Node.js 22 with TypeScript 5.x
- Express.js for the API server
- Prisma ORM with PostgreSQL
- React 19 with Vite for the frontend

## Architecture
- Monorepo with pnpm workspaces
- packages/api — Express REST API
- packages/web — React SPA
- packages/shared — Shared types and utilities

## Commands
- pnpm dev — Start all services
- pnpm test — Run vitest across all packages
- pnpm lint — ESLint + Prettier check
- pnpm db:migrate — Run Prisma migrations

## Conventions
- Use barrel exports (index.ts) for public APIs
- Error responses use RFC 7807 Problem Details format
- All API endpoints require authentication except /health

JetBrains AI / Junie

.aiassistant/rules/*.md

markdown

# Kotlin Conventions

## Language Features
- Use Kotlin 2.x with coroutines for async work
- Prefer data classes for DTOs and value objects
- Use sealed classes/interfaces for domain errors
- Extension functions over utility classes

## Spring Boot
- Constructor injection (no field injection)
- Use @ConfigurationProperties over @Value
- Prefer WebFlux for reactive endpoints
- Use Spring Security with method-level security

## Testing
- JUnit 5 with Kotest assertions
- MockK for mocking (not Mockito)
- Testcontainers for integration tests
- Use @Nested for test organization

KEY DIFFERENCES

1. Hierarchy support

Gemini CLI: Supported. JetBrains AI / Junie: Not supported.

2. Global config

Gemini CLI: Supported. JetBrains AI / Junie: Not supported.

3. Ignore file

Gemini CLI: Not supported. JetBrains AI / Junie: .aiignore.

4. IDE integration

Gemini CLI: CLI. JetBrains AI / Junie: Supported.

WHICH SHOULD I USE?

Recommendation

Choose based on your IDE/CLI preference. If you use Gemini CLI, configure GEMINI.md. If you use JetBrains AI / Junie, configure .aiassistant/rules/*.md. Many projects include config files for multiple tools so each team member can use their preferred editor.

PORTABILITY TIP

sync-instructions.sh

bash

# Maintain a single source of truth:
cp AI-INSTRUCTIONS.md CLAUDE.md
cp AI-INSTRUCTIONS.md .cursorrules
cp AI-INSTRUCTIONS.md AGENTS.md