Advanced model settings

Context window size and token costs

In most cases, you can safely ignore aider's warning about unknown context window size and model costs.

{: .note } Aider never enforces token limits, it only reports token limit errors from the API provider. You probably don't need to configure aider with the proper token limits for unusual models.

But, you can register context window limits and costs for models that aren't known to aider. Create a .aider.model.metadata.json file in one of these locations:

• Your home directory.
• The root if your git repo.
• The current directory where you launch aider.
• Or specify a specific file with the --model-metadata-file <filename> switch.

If the files above exist, they will be loaded in that order. Files loaded last will take priority.

The json file should be a dictionary with an entry for each model, as follows:

{
    "deepseek/deepseek-chat": {
        "max_tokens": 4096,
        "max_input_tokens": 32000,
        "max_output_tokens": 4096,
        "input_cost_per_token": 0.00000014,
        "output_cost_per_token": 0.00000028,
        "litellm_provider": "deepseek",
        "mode": "chat"
    }
}

{: .tip } Use a fully qualified model name with a provider/ at the front in the .aider.model.metadata.json file. For example, use deepseek/deepseek-chat, not just deepseek-chat. That prefix should match the litellm_provider field.

Contribute model metadata

Aider relies on litellm's model_prices_and_context_window.json file for model metadata.

Consider submitting a PR to that file to add missing models.

Model settings

Aider has a number of settings that control how it works with different models. These model settings are pre-configured for most popular models. But it can sometimes be helpful to override them or add settings for a model that aider doesn't know about.

Configuration file locations

You can override or add settings for any model by creating a .aider.model.settings.yml file in one of these locations:

• Your home directory.
• The root of your git repo.
• The current directory where you launch aider.
• Or specify a specific file with the --model-settings-file <filename> switch.

If the files above exist, they will be loaded in that order. Files loaded last will take priority.

The YAML file should be a list of dictionary objects for each model.

Passing extra params to litellm.completion

The extra_params attribute of model settings is used to pass arbitrary extra parameters to the litellm.completion() call when sending data to the given model.

For example:

- name: some-provider/my-special-model
  extra_params:
    extra_headers:
      Custom-Header: value
    max_tokens: 8192

You can use the special model name aider/extra_params to define extra_params that will be passed to litellm.completion() for all models. Only the extra_params dict is used from this special model name.

For example:

- name: aider/extra_params
  extra_params:
    extra_headers:
      Custom-Header: value
    max_tokens: 8192

These settings will be merged with any model-specific settings, with the aider/extra_params settings taking precedence for any direct conflicts.

Default model settings

Below are all the pre-configured model settings to give a sense for the settings which are supported.

You can also look at the ModelSettings class in models.py file for more details about all of the model setting that aider supports.

The first entry shows all the settings, with their default values. For a real model, you just need to include whichever fields that you want to override the defaults.

- name: (default values)
  edit_format: whole
  weak_model_name: null
  use_repo_map: false
  send_undo_reply: false
  lazy: false
  overeager: false
  reminder: user
  examples_as_sys_msg: false
  extra_params: null
  cache_control: false
  caches_by_default: false
  use_system_prompt: true
  use_temperature: true
  streaming: true
  editor_model_name: null
  editor_edit_format: null
  reasoning_tag: null
  remove_reasoning: null
  system_prompt_prefix: null
  accepts_settings: null

- name: anthropic.claude-opus-4-20250514-v1:0
  edit_format: diff
  weak_model_name: anthropic.claude-3-5-haiku-20241022-v1:0
  use_repo_map: true
  extra_params:
    extra_headers:
      anthropic-beta: prompt-caching-2024-07-31,pdfs-2024-09-25,output-128k-2025-02-19
    max_tokens: 32000
  cache_control: true
  editor_model_name: anthropic.claude-sonnet-4-20250514-v1:0
  editor_edit_format: editor-diff
  accepts_settings:
  - thinking_tokens

- name: anthropic.claude-sonnet-4-20250514-v1:0
  edit_format: diff
  weak_model_name: anthropic.claude-3-5-haiku-20241022-v1:0
  use_repo_map: true
  extra_params:
    extra_headers:
      anthropic-beta: prompt-caching-2024-07-31,pdfs-2024-09-25,output-128k-2025-02-19
    max_tokens: 64000
  cache_control: true
  editor_model_name: anthropic.claude-sonnet-4-20250514-v1:0
  editor_edit_format: editor-diff
  accepts_settings:
  - thinking_tokens

- name: anthropic/claude-3-5-haiku-20241022
  edit_format: diff
  weak_model_name: anthropic/claude-3-5-haiku-20241022
  use_repo_map: true
  extra_params:
    extra_headers:
      anthropic-beta: prompt-caching-2024-07-31,pdfs-2024-09-25
  cache_control: true

- name: anthropic/claude-3-5-sonnet-20240620
  edit_format: diff
  weak_model_name: anthropic/claude-3-5-haiku-20241022
  use_repo_map: true
  examples_as_sys_msg: true
  extra_params:
    extra_headers:
      anthropic-beta: prompt-caching-2024-07-31,pdfs-2024-09-25
    max_tokens: 8192
  cache_control: true
  editor_model_name: anthropic/claude-3-5-sonnet-20240620
  editor_edit_format: editor-diff

- name: anthropic/claude-3-5-sonnet-20241022
  edit_format: diff
  weak_model_name: anthropic/claude-3-5-haiku-20241022
  use_repo_map: true
  examples_as_sys_msg: true
  extra_params:
    extra_headers:
      anthropic-beta: prompt-caching-2024-07-31,pdfs-2024-09-25
    max_tokens: 8192
  cache_control: true
  editor_model_name: anthropic/claude-3-5-sonnet-20241022
  editor_edit_format: editor-diff

- name: anthropic/claude-3-5-sonnet-latest
  edit_format: diff
  weak_model_name: anthropic/claude-3-5-haiku-20241022
  use_repo_map: true
  examples_as_sys_msg: true
  extra_params:
    extra_headers:
      anthropic-beta: prompt-caching-2024-07-31,pdfs-2024-09-25
    max_tokens: 8192
  cache_control: true
  editor_model_name: anthropic/claude-3-5-sonnet-20241022
  editor_edit_format: editor-diff

- name: anthropic/claude-3-7-sonnet-20250219
  edit_format: diff
  weak_model_name: anthropic/claude-3-5-haiku-20241022
  use_repo_map: true
  overeager: true
  examples_as_sys_msg: true
  extra_params:
    extra_headers:
      anthropic-beta: prompt-caching-2024-07-31,pdfs-2024-09-25,output-128k-2025-02-19
    max_tokens: 64000
  cache_control: true
  editor_model_name: anthropic/claude-3-7-sonnet-20250219
  editor_edit_format: editor-diff
  accepts_settings:
  - thinking_tokens

- name: anthropic/claude-3-7-sonnet-latest
  edit_format: diff
  weak_model_name: anthropic/claude-3-5-haiku-20241022
  use_repo_map: true
  overeager: true
  examples_as_sys_msg: true
  extra_params:
    extra_headers:
      anthropic-beta: prompt-caching-2024-07-31,pdfs-2024-09-25,output-128k-2025-02-19
    max_tokens: 64000
  cache_control: true
  editor_model_name: anthropic/claude-3-7-sonnet-latest
  editor_edit_format: editor-diff
  accepts_settings:
  - thinking_tokens

- name: anthropic/claude-3-haiku-20240307
  weak_model_name: anthropic/claude-3-haiku-20240307
  examples_as_sys_msg: true
  extra_params:
    extra_headers:
      anthropic-beta: prompt-caching-2024-07-31,pdfs-2024-09-25
  cache_control: true

- name: anthropic/claude-opus-4-20250514
  edit_format: diff
  weak_model_name: anthropic/claude-3-5-haiku-20241022
  use_repo_map: true
  extra_params:
    extra_headers:
      anthropic-beta: prompt-caching-2024-07-31,pdfs-2024-09-25,output-128k-2025-02-19
    max_tokens: 32000
  cache_control: true
  editor_model_name: anthropic/claude-sonnet-4-20250514
  editor_edit_format: editor-diff
  accepts_settings:
  - thinking_tokens

- name: anthropic/claude-sonnet-4-20250514
  edit_format: diff
  weak_model_name: anthropic/claude-3-5-haiku-20241022
  use_repo_map: true
  extra_params:
    extra_headers:
      anthropic-beta: prompt-caching-2024-07-31,pdfs-2024-09-25,output-128k-2025-02-19
    max_tokens: 64000
  cache_control: true
  editor_model_name: anthropic/claude-sonnet-4-20250514
  editor_edit_format: editor-diff
  accepts_settings:
  - thinking_tokens

- name: azure/gpt-4.1
  edit_format: diff
  weak_model_name: azure/gpt-4.1-mini
  use_repo_map: true
  reminder: sys
  editor_model_name: azure/gpt-4.1-mini

- name: azure/gpt-4.1-mini
  edit_format: diff
  use_repo_map: true
  reminder: sys

- name: azure/gpt-5
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5-2025-08-07
  edit_format: diff
  weak_model_name: azure/gpt-5-nano-2025-08-07
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5-chat
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5-chat-latest
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5-mini
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5-mini-2025-08-07
  edit_format: diff
  weak_model_name: azure/gpt-5-nano-2025-08-07
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5-nano
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5-nano-2025-08-07
  edit_format: diff
  weak_model_name: azure/gpt-5-nano-2025-08-07
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5-pro
  edit_format: diff
  weak_model_name: azure/gpt-5-mini
  use_repo_map: true
  examples_as_sys_msg: true
  use_temperature: false
  streaming: false
  editor_model_name: azure/gpt-5
  editor_edit_format: editor-diff
  system_prompt_prefix: 'Formatting re-enabled. '
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5.1
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5.1-2025-11-13
  edit_format: diff
  weak_model_name: azure/gpt-5-nano-2025-08-07
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5.1-chat
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5.1-chat-latest
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5.2
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5.2-2025-12-11
  edit_format: diff
  weak_model_name: azure/gpt-5-nano-2025-08-07
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5.2-chat-latest
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5.3
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5.3-chat-latest
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5.3-pro
  edit_format: diff
  weak_model_name: azure/gpt-5-mini
  use_repo_map: true
  examples_as_sys_msg: true
  use_temperature: false
  streaming: false
  editor_model_name: azure/gpt-5.3
  editor_edit_format: editor-diff
  system_prompt_prefix: 'Formatting re-enabled. '
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5.4
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5.4-chat-latest
  edit_format: diff
  weak_model_name: azure/gpt-5-nano
  use_repo_map: true
  use_temperature: false
  accepts_settings:
  - reasoning_effort

- name: azure/gpt-5.4-pro
  edit_format: diff
  weak_model_name: azure/gpt-5-mini
  use_repo_map: true
  examples_as_sys_msg: true
  use_temperature: false
  streaming: false
  editor_model_name: azure/gpt-5.4
  editor_edit_format: editor-diff
  system_prompt_prefix: 'Formatting re-enabled. '
  accepts_settings:
  - reasoning_effort

- name: azure/o1
  edit_format: diff
  weak_model_name: azure/gpt-4o-mini
  use_repo_map: true
  use_temperature: false
  streaming: false
  editor_model_name: azure/gpt-4o
  editor_edit_format: editor-diff
  accepts_settings:
  - reasoning_effort

- name: azure/o1-mini
  weak_model_name: azure/gpt-4o-mini
  use_repo_map: true
  use_system_prompt: false
  use_temperature: false
  editor_model_name: azure/gpt-4o
  editor_edit_format: editor-diff

- name: azure/o1-preview
  edit_format: diff
  weak_model_name: azure/gpt-4o-mini
  use_repo_map: true
  use_system_prompt: false
  use_temperature: false
  editor_model_name: azure/gpt-4o
  editor_edit_format: editor-diff

- name: azure/o3
  edit_format: diff
  weak_model_name: azure/gpt-4.1-mini
  use_repo_map: true
  examples_as_sys_msg: true
  streaming: false
  editor_model_name: azure/gpt-4.1
  editor_edit_format: editor-diff
  system_prompt_prefix: 'Formatting re-enabled. '
  accepts_settings:
  - reasoning_effort

- name: azure/o3-mini
  edit_format: diff
  weak_model_name: azure/gpt-4o-mini
  use_repo_map: true
  use_temperature: false
  editor_model_name: azure/gpt-4o
  editor_edit_format: editor-diff
  system_prompt_prefix: 'Formatting re-enabled. '
  accepts_settings:
  - reasoning_effort

- name: azure/o3-pro
  edit_format: diff
  weak_model_name: azure/gpt-4.1-mini
  use_repo_map: true