Fusion vs Jules | agentconfig.ing

Fusion vs JulesComparisonUpdated 2026-03-16

SUMMARY

Fusion (IDE) uses mdc configuration while Jules (Agent) uses markdown. They differ on 5 of 11 compared features. Both tools provide AI-assisted development but take different approaches to project configuration.

FEATURE COMPARISON

Feature	Fusion	Jules	Notes
Config format	mdc	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	✗	✗
IDE integration	✓	Agent
Schema / structure	Hybrid (MDC frontmatter + 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	Fusion	Jules
Project instructions	AGENTS.md	AGENTS.md

SIDE-BY-SIDE CODE SAMPLES

Fusion

.builder/rules/*.mdc

mdc

---
description: React component conventions
globs: src/components/**/*.tsx
alwaysApply: false
---

# React Component Rules

## Structure
- Use functional components with TypeScript
- Define props interface above the component
- Export components as named exports

## Styling
- Use the project design system tokens for spacing and colors
- Prefer utility classes over custom CSS
- Keep component-specific styles colocated

## Patterns
- Wrap async data in Suspense boundaries
- Use forwardRef for reusable interactive components
- Keep components under 150 lines; extract hooks for logic

## Accessibility
- All interactive elements need aria-labels
- Use semantic HTML elements (nav, main, section)
- Ensure keyboard navigation works for custom widgets

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. Config format

Fusion: mdc. Jules: markdown.

2. Hierarchy support

Fusion: Not supported. Jules: Supported.

3. Subdirectory scoping

Fusion: Not supported. Jules: Supported.

4. IDE integration

Fusion: Supported. Jules: Agent.

5. Schema / structure

Fusion: Hybrid (MDC frontmatter + Markdown). Jules: Free-form (Markdown).

WHICH SHOULD I USE?

Recommendation

Choose based on your IDE/CLI preference. If you use Fusion, configure .builder/rules/*.mdc. 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