Aider Configuration - Google Gemini 2.5 Pro via OpenRouter

A production-ready Aider configuration file optimized for using Google Gemini 2.5 Pro through OpenRouter with enhanced UX features.

What This Does

This configuration file (`.aider.conf.yml`) customizes Aider's behavior with:

Instructions

When a user asks to set up or configure Aider with this configuration:

1. **Verify Aider is installed**

- Check if `aider` command exists

- If not, suggest installation: `pip install aider-chat` or `pipx install aider-chat`

2. **Determine config file location**

- Ask user if they want it in:

- Git repository root (project-specific)

- Home directory `~/.aider.conf.yml` (global default)

- Default to git root if in a repository

3. **Create the configuration file**

- Write the following to `.aider.conf.yml`:

```yaml

Main model

model: openrouter/google/gemini-2.5-pro-preview

Output settings

dark-mode: true

notifications: true

Git settings

gitignore: false

```

4. **Configure API key**

- Inform user they need an OpenRouter API key from https://openrouter.ai/

- Recommend setting it as environment variable: `export OPENROUTER_API_KEY=your_key_here`

- Or add to `.env` file in project root (which Aider auto-loads)

5. **Explain key settings**

- **model**: Uses Gemini 2.5 Pro through OpenRouter (requires OpenRouter API key)

- **dark-mode**: Optimized colors for dark terminals

- **notifications**: Terminal bell when responses complete

- **gitignore: false**: Prevents auto-adding `.aider*` files to `.gitignore`

6. **Optional customizations**

- Offer to add common optional settings:

- `--vim: true` for VI keybindings

- `--auto-test: true` if they have a test suite

- `--map-tokens: 2048` to adjust repo map size

- Custom `--lint-cmd` for their language

7. **Verify setup**

- Have user run `aider --help` to confirm installation

- Test with `aider` command to ensure config loads

- Check model selection with `aider --list-models gemini`

Examples

**User: "Set up Aider with Gemini"**

→ Create `.aider.conf.yml` in git root with Gemini config, guide through OpenRouter API key setup

**User: "I want Aider configured for my home directory"**

→ Create `~/.aider.conf.yml` instead of project-specific config

**User: "Add VI mode to my Aider config"**

→ Add `vim: true` to existing `.aider.conf.yml`

**User: "Configure Aider to run my pytest tests automatically"**

→ Add `auto-test: true` and `test-cmd: pytest` to config

Constraints

Additional Notes