Amp vs FusionComparisonUpdated 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
| Feature | Amp | Fusion |
|---|---|---|
| Config format | markdown | mdc |
| Hierarchy support | ✓ | ✗ |
| Global config | ✓ | ✗ |
| Project config | ✓ | ✓ |
| Subdirectory scoping | ✓ | ✗ |
| File inclusion / imports | ✗ | ✗ |
| Ignore file | ✗ | ✗ |
| IDE integration | CLI | ✓ |
| Schema / structure | Free-form (Markdown) | Hybrid (MDC frontmatter + Markdown) |
| Git committed | ✓ | ✓ |
| Encoding | UTF-8 | UTF-8 |
FILE MAPPING
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
Amp: markdown. Fusion: mdc.
Amp: Supported. Fusion: Not supported.
Amp: Supported. Fusion: Not supported.
Amp: Supported. Fusion: Not supported.
Amp: CLI. Fusion: Supported.
Amp: Free-form (Markdown). Fusion: Hybrid (MDC frontmatter + Markdown).
WHICH SHOULD I USE?
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
agentconfig.ing2026-03-16COMPARE(1)