Amp vs FusionUpdated 2026-03-16

SUMMARY

Amp (CLI) uses markdown configuration while Fusion (IDE) uses mdc. They differ on 6 of 11 compared features. Both tools provide AI-assisted development but take different approaches to project configuration.

FEATURE COMPARISON

FeatureAmpFusion
Config formatmarkdownmdc
Hierarchy support
Global config
Project config
Subdirectory scoping
File inclusion / imports
Ignore file
IDE integrationCLI
Schema / structureFree-form (Markdown)Hybrid (MDC frontmatter + Markdown)
Git committed
EncodingUTF-8UTF-8

FILE MAPPING

PurposeAmpFusion
Project instructionsAGENTS.mdAGENTS.md
Project rules.agents/checks/*.md.builder/rules/*.mdc

SIDE-BY-SIDE CODE SAMPLES

Amp
AGENTS.md
markdown
# Agent Instructions

## Project Context
Go microservices monorepo using Bazel for builds.

## Build & Test
- Build all: bazel build //...
- Test all: bazel test //...
- Integration tests: docker compose up -d && bazel test //integration/...
- Lint: golangci-lint run ./...

## Code Conventions
- All services follow standard layout in /cmd and /internal
- Use structured logging with slog
- Error wrapping with fmt.Errorf("op: %w", err)
- See @docs/api-style-guide.md for API conventions

## Cross-Repo References
- Shared proto definitions in sourcegraph/proto
- Common Go libraries in sourcegraph/lib

## Security
- Never log sensitive data (tokens, passwords, PII)
- All external inputs must be validated
- Use parameterized queries for database access

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

KEY DIFFERENCES

1. Config format

Amp: markdown. Fusion: mdc.

2. Hierarchy support

Amp: Supported. Fusion: Not supported.

3. Global config

Amp: Supported. Fusion: Not supported.

4. Subdirectory scoping

Amp: Supported. Fusion: Not supported.

5. IDE integration

Amp: CLI. Fusion: Supported.

6. Schema / structure

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

WHICH SHOULD I USE?

Recommendation

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

SEE ALSO

Tool pages:
File references:
agentconfig.ing2026-03-16COMPARE(1)