Aider vs Gemini CLIComparisonUpdated 2026-03-16
SUMMARY
Aider (CLI) uses markdown configuration while Gemini CLI (CLI) uses markdown. They differ on 3 of 11 compared features. Both tools provide AI-assisted development but take different approaches to project configuration.
FEATURE COMPARISON
| Feature | Aider | Gemini CLI |
|---|---|---|
| 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 | Gemini CLI |
|---|---|---|
| Settings / configuration | .aider.conf.yml | .gemini/settings.json |
| Project instructions | CONVENTIONS.md | GEMINI.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
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
Aider: Not supported. Gemini CLI: Supported.
Aider: Supported. Gemini CLI: Not supported.
Aider: .aiderignore. Gemini CLI: Not supported.
WHICH SHOULD I USE?
Choose based on your IDE/CLI preference. If you use Aider, configure .aider.conf.yml. 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
SEE ALSO
Tool pages:
File references:
agentconfig.ing2026-03-16COMPARE(1)