Fusion vs Gemini CLI | agentconfig.ing

Fusion vs Gemini CLIComparisonUpdated 2026-03-16

SUMMARY

Fusion (IDE) uses mdc configuration while Gemini CLI (CLI) 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	Gemini CLI	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	✓	CLI
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	Gemini CLI
Project instructions	AGENTS.md	GEMINI.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

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

KEY DIFFERENCES

1. Config format

Fusion: mdc. Gemini CLI: markdown.

2. Hierarchy support

Fusion: Not supported. Gemini CLI: Supported.

3. Global config

Fusion: Not supported. Gemini CLI: Supported.

4. IDE integration

Fusion: Supported. Gemini CLI: CLI.

5. Schema / structure

Fusion: Hybrid (MDC frontmatter + Markdown). Gemini CLI: 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 Gemini CLI, configure GEMINI.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