Aider vs OpenCodeComparisonUpdated 2026-03-16
SUMMARY
Aider (CLI) uses markdown configuration while OpenCode (CLI) uses markdown. They differ on 2 of 11 compared features. Both tools provide AI-assisted development but take different approaches to project configuration.
FEATURE COMPARISON
| Feature | Aider | OpenCode |
|---|---|---|
| Config format | markdown | markdown |
| Hierarchy support | ✗ | ✓ |
| Global config | ✓ | ✓ |
| Project config | ✓ | ✓ |
| Subdirectory scoping | ✓ | ✓ |
| File inclusion / imports | ✗ | ✗ |
| Ignore file | .aiderignore | ✗ |
| IDE integration | CLI | CLI |
| Schema / structure | Free-form (Markdown) | Free-form (Markdown) |
| Git committed | ✓ | ✓ |
| Encoding | UTF-8 | UTF-8 |
FILE MAPPING
| Purpose | Aider | OpenCode |
|---|---|---|
| Settings / configuration | .aider.conf.yml | opencode.json |
| Project instructions | CONVENTIONS.md | AGENTS.md |
SIDE-BY-SIDE CODE SAMPLES
Aider
CONVENTIONS.md
markdown
# Project Conventions
## Language
- TypeScript strict mode, no `any` types
- Prefer const over let, never use var
- Use template literals over string concatenation
## Architecture
- Feature-based folder structure under src/features/
- Each feature exports through an index.ts barrel file
- Shared utilities go in src/lib/
## Error Handling
- Use Result<T, E> pattern for expected failures
- Throw only for programmer errors
- Always log errors with structured context
## Testing
- Colocate tests next to source files (*.test.ts)
- Use factories for test data, not fixtures
- Integration tests in __tests__/ directories
OpenCode
AGENTS.md
markdown
# Project Instructions
## Overview
This is a TypeScript monorepo using pnpm workspaces.
## Code Style
- Use strict TypeScript with no implicit any
- Prefer functional components with hooks
- All exports should be named (no default exports)
## Architecture
- /packages/core — shared business logic
- /packages/ui — React component library
- /apps/web — Next.js frontend
## Build & Test
Run tests with: pnpm test
Build all packages: pnpm build
All PRs must have >80% coverage on changed files.
## Conventions
- Use conventional commits (feat:, fix:, chore:)
- Prefer composition over inheritance
- See @docs/api-guidelines.md for API design patterns
KEY DIFFERENCES
Aider: Not supported. OpenCode: Supported.
Aider: .aiderignore. OpenCode: Not supported.
WHICH SHOULD I USE?
Choose based on your IDE/CLI preference. If you use Aider, configure .aider.conf.yml. If you use OpenCode, 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
SEE ALSO
File references:
agentconfig.ing2026-03-16COMPARE(1)