JetBrains AI / Junie vs Jules

JetBrains AI / Junie vs JulesComparisonUpdated 2026-03-16

SUMMARY

JetBrains AI / Junie (IDE) uses markdown configuration while Jules (Agent) 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	JetBrains AI / Junie	Jules	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	✓	Agent
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	JetBrains AI / Junie	Jules
Settings / configuration	.noai	.gemini/settings.json

SIDE-BY-SIDE CODE SAMPLES

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

Jules

AGENTS.md

markdown

# Agent Instructions

## Project
A Django REST API serving a React frontend.

## Setup
- Python 3.12 with Poetry
- PostgreSQL 15
- Redis for caching and Celery broker

## Key Commands
- poetry run python manage.py runserver
- poetry run pytest
- poetry run mypy .

## Pull Request Guidelines
- Keep PRs focused on a single issue
- Add tests for all new functionality
- Update API docs in docs/api/ if endpoints change
- Run the linter: poetry run ruff check .

## Architecture Notes
- apps/core/ — shared models and utilities
- apps/api/v2/ — current API version
- apps/tasks/ — Celery background tasks

KEY DIFFERENCES

1. Hierarchy support

JetBrains AI / Junie: Not supported. Jules: Supported.

2. Subdirectory scoping

JetBrains AI / Junie: Not supported. Jules: Supported.

3. Ignore file

JetBrains AI / Junie: .aiignore. Jules: Not supported.

4. IDE integration

JetBrains AI / Junie: Supported. Jules: Agent.

WHICH SHOULD I USE?

Recommendation

Choose based on your IDE/CLI preference. If you use JetBrains AI / Junie, configure .aiassistant/rules/*.md. If you use Jules, configure AGENTS.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