Use Autohand models in Aider

Prerequisites

• An Autohand account. Sign up or sign in to Console. The Free plan includes Fantail. Moa requires the Pro plan or above.
• An Autohand API key. The first step shows how to create one.
• Aider. Install it with python -m pip install aider-install and then run aider-install.

Step 1: Create an Autohand API key

1. Sign in to Autohand Console.
2. Open API Keys and select Create API Key.
3. Enter a name that identifies the agent and machine, for example aider-laptop.
4. Select Create Key and copy the value. Console shows the key only once.

Step 2: Store the key in an environment variable

Store the key in an environment variable so it stays out of configuration files and source control.

# macOS and Linux (add the line to ~/.zshrc or ~/.bashrc to keep it)
export AUTOHAND_API_KEY="your-api-key"

# Windows PowerShell (current session)
$env:AUTOHAND_API_KEY = "your-api-key"

# Windows (persist for new sessions)
setx AUTOHAND_API_KEY "your-api-key"

Confirm that the key works and that your plan can see the models:

curl https://api.autohand.ai/v1/models \
  -H "Authorization: Bearer $AUTOHAND_API_KEY"

The response lists fantail, and moa when your plan includes it. A 401 response means the key is missing or not recognised.

Step 3: Point Aider at Autohand

Aider reads the OpenAI-compatible endpoint from OPENAI_API_BASE and the key from OPENAI_API_KEY. Set both from your Autohand values:

export OPENAI_API_BASE="https://api.autohand.ai/v1"
export OPENAI_API_KEY="$AUTOHAND_API_KEY"

$env:OPENAI_API_BASE = "https://api.autohand.ai/v1"
$env:OPENAI_API_KEY = $env:AUTOHAND_API_KEY

If you also use OpenAI directly, pass the values as options instead, so the variables stay free for OpenAI:

aider --model openai/fantail \
  --openai-api-base https://api.autohand.ai/v1 \
  --openai-api-key "$AUTOHAND_API_KEY"

To keep the settings with a repository, add a .aider.conf.yml file to the repository root. Keep the key out of this file.

# .aider.conf.yml
model: openai/moa
weak-model: openai/fantail
editor-model: openai/fantail
openai-api-base: https://api.autohand.ai/v1

Step 4: Choose Fantail or Moa and set the limits

Aider does not know the Autohand models by default, so it warns about unknown context limits. Add a .aider.model.metadata.json file to your home directory or repository root to set the limits:

{
  "openai/fantail": {
    "max_input_tokens": 262144,
    "max_output_tokens": 16000,
    "input_cost_per_token": 0,
    "output_cost_per_token": 0,
    "litellm_provider": "openai",
    "mode": "chat"
  },
  "openai/moa": {
    "max_input_tokens": 1048576,
    "max_output_tokens": 262144,
    "input_cost_per_token": 0,
    "output_cost_per_token": 0,
    "litellm_provider": "openai",
    "mode": "chat"
  }
}

Aider has no Autohand prices, so the costs are set to 0. Check usage in Console. You can also pass the file with --model-metadata-file.

Step 5: Run a test prompt

aider --model openai/fantail --message "Summarize what this repository does in three sentences."

A text answer confirms that Aider reaches Autohand. An AuthenticationError that mentions Credential not recognised means the key is wrong.

Use Fantail for the weak and editor models

Aider has no subagents. It uses two helper roles that you can assign to Fantail:

• The weak model writes commit messages and summarizes chat history. Set it with --weak-model openai/fantail.
• The editor model turns the main model's plan into file edits in architect mode. Set it with --editor-model openai/fantail.

To plan with Moa and edit with Fantail, start Aider in architect mode:

aider --architect --model openai/moa --editor-model openai/fantail --weak-model openai/fantail

To make these roles the default for each model, add a .aider.model.settings.yml file:

- name: openai/moa
  edit_format: diff
  weak_model_name: openai/fantail
  editor_model_name: openai/fantail
  editor_edit_format: editor-diff
  use_repo_map: true

- name: openai/fantail
  edit_format: diff
  weak_model_name: openai/fantail
  use_repo_map: true

Troubleshooting

Next steps

• Use Autohand models in other coding agents
• Compare Autohand models
• Fantail model reference
• Moa model reference
• Create and protect an API key