The latest feature in Braintrust is the implementation of Copilot autocomplete in its UI. This feature allows users to leverage their existing API keys with models like gpt-4o-2024-08-06, Claude 3.5 Sonnet, LLaMa 3.1, Gemini, Mistral and others. The autocomplete is enabled for everyone who has configured at least one AI provider key, and it uses the user's selected model to provide intelligent completions based on context from other data fields. Braintrust has captured completion data from its staging account and run initial evaluations which showed that the default model performs almost as well as some of the more expensive options, with room for improvement through additional data and customer feedback. The new feature is available for everyone who already has a Braintrust account or can sign up for free to try it out, and users are encouraged to provide feedback to help improve the feature.