Aider AI Pair Programming

Configure and use Aider to collaborate with AI on code changes. Aider understands your entire codebase, makes coordinated edits across multiple files, and automatically commits changes with meaningful messages.

What This Skill Does

Guides you through setting up and using Aider's configuration file (`.aider.conf.yml`) to customize AI-assisted coding sessions. Aider can use Claude, GPT-4, DeepSeek, and other LLMs to write, refactor, and debug code while maintaining git history.

Instructions

Initial Setup

1. **Create Configuration File**

- Place `.aider.conf.yml` in your git repository root or home directory

- Start with minimal configuration and expand as needed

- Only OpenAI and Anthropic API keys can be stored in YAML (use `.env` for other providers)

2. **Choose Your Main Model**

```yaml

# Use Claude Sonnet (recommended for code)

model: anthropic/claude-3-7-sonnet-20250219

# Or GPT-4o

model: gpt-4o

# Or DeepSeek (cost-effective)

model: deepseek/deepseek-chat

```

3. **Configure API Access**

```yaml

# For Anthropic

anthropic-api-key: sk-ant-xxx

# For OpenAI

openai-api-key: sk-xxx

# For other providers, use .env file or set-env

set-env:

- DEEPSEEK_API_KEY=sk-xxx

```

Essential Configuration Options

4. **Model Settings**

```yaml

# Weaker model for commit messages (saves costs)

weak-model: gpt-4o-mini

# Editor model for quick fixes

editor-model: gpt-4o-mini

# Repository map token limit (0 to disable)

map-tokens: 1024

```

5. **Git Integration**

```yaml

# Auto-commit changes (default: true)

auto-commits: true

# Allow commits when repo is dirty (default: true)

dirty-commits: true

# Attribution options

attribute-author: true

attribute-committer: true

attribute-commit-message-author: false

```

6. **Output Preferences**

```yaml

# Terminal appearance

dark-mode: true

pretty: true

stream: true

# Show diffs before committing

show-diffs: true

```

Advanced Features

7. **Automatic Testing and Linting**

```yaml

# Run tests after changes

test-cmd: pytest

auto-test: true

# Lint and fix automatically

lint-cmd:

- "python: ruff check --fix"

- "typescript: eslint --fix"

auto-lint: true

```

8. **Voice Coding**

```yaml

voice-format: wav

voice-language: en

voice-input-device: "Built-in Microphone"

```

9. **Caching for Performance**

```yaml

# Enable prompt caching (reduces API costs)

cache-prompts: true

# Keep cache warm for faster responses

cache-keepalive-pings: 2

```

10. **Edit Formats**

```yaml

# Let Aider choose best format for model (recommended)

# Or force specific format:

edit-format: diff

# Options: diff, whole, diff-fenced, udiff

# Use architect mode for complex refactors

architect: false

```

Using Aider

11. **Start Aider Session**

```bash

# Launch with config

aider

# Add specific files to context

aider src/main.py tests/test_main.py

# One-shot mode

aider --message "Add error handling to login function"

```

12. **In-Chat Commands**

- `/add <file>` - Add file to chat context

- `/drop <file>` - Remove file from context

- `/commit` - Commit pending changes

- `/undo` - Undo last change

- `/run <cmd>` - Run shell command

- `/test` - Run configured tests

- `/lint` - Run linter

- `/exit` - Exit aider

13. **File Management**

```yaml

# Specify files to always include

file:

- src/core.py

- config.yaml

# Read-only reference files

read:

- README.md

- docs/architecture.md

# Ignore patterns

aiderignore: .aiderignore

```

Example Configurations

14. **Minimal Setup (Claude)**

```yaml

model: anthropic/claude-3-7-sonnet-20250219

anthropic-api-key: sk-ant-xxx

dark-mode: true

auto-commits: true

```

15. **Cost-Optimized Setup**

```yaml

model: deepseek/deepseek-chat

weak-model: gpt-4o-mini

cache-prompts: true

map-tokens: 512

set-env:

- DEEPSEEK_API_KEY=sk-xxx

```

16. **Full-Featured Setup**

```yaml

model: gpt-4o

weak-model: gpt-4o-mini

editor-model: gpt-4o-mini

openai-api-key: sk-xxx

dark-mode: true

show-diffs: true

stream: true

auto-commits: true

attribute-author: true

test-cmd: pytest -v

auto-test: true

lint-cmd:

- "python: ruff check --fix"

auto-lint: true

cache-prompts: true

map-tokens: 2048

```

Best Practices

Troubleshooting

Example Usage

```bash

Create config file

cat > .aider.conf.yml <<EOF

model: anthropic/claude-3-7-sonnet-20250219

anthropic-api-key: $ANTHROPIC_API_KEY

dark-mode: true

auto-commits: true

show-diffs: true

map-tokens: 2048

EOF

Start coding session

aider

In chat:

"Add input validation to the user registration function"

"Refactor the database queries to use async/await"

"Write unit tests for the new API endpoints"

```

Important Notes