Simon Willison’s Weblog

Introducing Zed AI (via) The Zed open source code editor (from the original Atom team) already had GitHub Copilot autocomplete support, but now they're introducing their own additional suite of AI features powered by Anthropic (though other providers can be configured using additional API keys).

The focus is on an assistant panel - a chatbot interface with additional commands such as /file myfile.py to insert the contents of a project file - and an inline transformations mechanism for prompt-driven refactoring of selected code.

The most interesting part of this announcement is that it reveals a previously undisclosed upcoming Claude feature from Anthropic:

For those in our closed beta, we're taking this experience to the next level with Claude 3.5 Sonnet's Fast Edit Mode. This new capability delivers mind-blowingly fast transformations, approaching real-time speeds for code refactoring and document editing.

LLM-based coding tools frequently suffer from the need to output the content of an entire file even if they are only changing a few lines - getting models to reliably produce valid diffs is surprisingly difficult.

This "Fast Edit Mode" sounds like it could be an attempt to resolve that problem. Models that can quickly pipe through copies of their input while applying subtle changes to that flow are an exciting new capability.