Aider vs Gemini Code AssistComparisonUpdated 2026-03-18
SUMMARY
Aider (CLI) uses markdown configuration while Gemini Code Assist (IDE) uses markdown. They differ on 4 of 11 compared features. Both tools provide AI-assisted development but take different approaches to project configuration.
FEATURE COMPARISON
| Feature | Aider | Gemini Code Assist |
|---|---|---|
| Config format | markdown | markdown |
| Hierarchy support | ✗ | ✓ |
| Global config | ✓ | ✗ |
| Project config | ✓ | ✓ |
| Subdirectory scoping | ✓ | ✓ |
| File inclusion / imports | ✗ | ✗ |
| Ignore file | .aiderignore | ✗ |
| IDE integration | CLI | ✓ |
| Schema / structure | Free-form (Markdown) | Free-form (Markdown) |
| Git committed | ✓ | ✓ |
| Encoding | UTF-8 | UTF-8 |
FILE MAPPING
| Purpose | Aider | Gemini Code Assist |
|---|---|---|
| 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 Code Assist
GEMINI.md
markdown
# Project Rules
## Overview
E-commerce platform built with Go microservices and React frontend.
All services communicate via gRPC with Protocol Buffers.
## Go Services
- Follow standard Go project layout (cmd/, internal/, pkg/)
- Use structured logging with slog (not log or fmt.Println)
- Error handling: always wrap errors with fmt.Errorf("%w", err)
- Database access through repository pattern in internal/repo/
- All public functions must have godoc comments
## API Design
- Proto files live in proto/ directory with buf for linting
- Use field masks for partial updates
- Pagination via cursor-based tokens, not offset
## Testing
- Table-driven tests for all business logic
- Use testcontainers-go for integration tests
- Minimum 80% coverage on internal/ packages
- Mock external services with gomock interfaces
## Do Not
- Use global variables or init() functions
- Import internal packages across service boundaries
- Commit generated .pb.go files (CI generates them)
KEY DIFFERENCES
Aider: Not supported. Gemini Code Assist: Supported.
Aider: Supported. Gemini Code Assist: Not supported.
Aider: .aiderignore. Gemini Code Assist: Not supported.
Aider: CLI. Gemini Code Assist: Supported.
WHICH SHOULD I USE?
Choose based on your IDE/CLI preference. If you use Aider, configure .aider.conf.yml. If you use Gemini Code Assist, 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.ing2026-03-18COMPARE(1)