Change directory into your codebase

Anthropic

To work with Anthropic's models, you need to provide your Anthropic API key either in the ANTHROPIC_API_KEY environment variable or via the --anthropic-api-key command line switch.

First, install aider:

{% include install.md %}

Then configure your API keys:

export ANTHROPIC_API_KEY=<key> # Mac/Linux
setx   ANTHROPIC_API_KEY <key> # Windows, restart shell after setx

Start working with aider and Anthropic on your codebase:

# Change directory into your codebase
cd /to/your/project

# Aider uses Claude 3.7 Sonnet by default
aider

# List models available from Anthropic
aider --list-models anthropic/

{: .tip } Anthropic has very low rate limits. You can access all the Anthropic models via OpenRouter or Google Vertex AI with more generous rate limits.

You can use aider --model <model-name> to use any other Anthropic model. For example, if you want to use a specific version of Opus you could do aider --model claude-3-opus-20240229.

Thinking tokens

Aider can work with Sonnet 3.7's new thinking tokens, but does not ask Sonnet to use thinking tokens by default.

Enabling thinking currently requires manual configuration. You need to add the following to your .aider.model.settings.yml model settings file. Adjust the budget_tokens value to change the target number of thinking tokens.

- name: anthropic/claude-3-7-sonnet-20250219
  edit_format: diff
  weak_model_name: anthropic/claude-3-5-haiku-20241022
  use_repo_map: true
  examples_as_sys_msg: true
  use_temperature: false
  extra_params:
    extra_headers:
      anthropic-beta: prompt-caching-2024-07-31,pdfs-2024-09-25,output-128k-2025-02-19
    max_tokens: 64000
    thinking:
      type: enabled
      budget_tokens: 32000 # Adjust this number
  cache_control: true
  editor_model_name: anthropic/claude-3-7-sonnet-20250219
  editor_edit_format: editor-diff

More streamlined support will be coming soon.