Models

Use /model to choose a model. fx remembers your selection for each provider.

Browse and select

Type /model and search by name, or press ctrl+p to switch models without losing the prompt you are typing.

The available models depend on your provider. Use /provider to change it. A custom connection uses the model IDs understood by its endpoint.

To see the available IDs from your terminal:

$fx models

If fx is already responding, the new model takes over on the next turn.

Reasoning effort

After choosing a model with /model, select a reasoning effort if the model supports it. Higher effort gives the model more room to reason and can take longer. Choose default to use the model's default effort.

You can also choose a different model and effort for each subagent.

Fast mode

Use /fast to turn faster inference on or off for models that support it. fx saves your preference.

Temporary overrides

Choose a provider and model when starting fx:

fx --provider gateway --model '<model-id>'

Or choose a model for one prompt:

fx ask --model '<model-id>' "Review the changes in this branch"

These flags leave your saved defaults unchanged. For fx ask, set FX_PROVIDER when you also need a different provider. You can use the same environment variables with fx acp.

AI Gateway routing

One AI Gateway model may be available from several inference providers. Use provider_order to prefer specific providers, and provider_strict to prevent fallback outside that list:

{
  "provider_order": ["bedrock", "anthropic"],
  "provider_strict": true
}

These settings work in .fx.json and ~/.fx/settings.json. For one request:

fx ask --provider-order bedrock,anthropic --provider-strict "Review this change"

Use provider slugs from the AI Gateway model catalog. fx ask --json returns the provider that served the last request in resolved_provider when AI Gateway reports it.

Selection order

If fx starts with an unexpected model, check --model and FX_MODEL first: both override saved preferences, and --model takes precedence. Workspace preferences in ~/.fx/settings.json override global preferences. Use /status to check the current selection. See Configuration for settings and scopes.

AI Gateway catalogs

AI Gateway can include models available to your selected Vercel team. To use another team's catalog, change teams.