btw vs D-ID

btw assembles context about an R session — packages, documentation, files, data frames — and hands it to an LLM through ellmer, with btw_app() as a chat interface. Over the last year it has grown well past context assembly: LLMs can document, check, test and measure coverage of a package, read CLAUDE.md and AGENTS.md as project context, fetch skills from packages or GitHub, and inspect the source of any installed namespace. Much of this is now reachable from a terminal CLI rather than only from an R prompt.

The direction is from describing a session to operating on it, and from inside R to outside it. Each release adds either a tool group that lets a model do something (document, check, test, cover; read namespace source; fetch skill resources) or a CLI command that removes the need to start R first. The 1.2.0 tool renaming — session becoming sessioninfo, search becoming cran, files_read_text_file becoming files_read — reads as the naming cleanup you do when you expect a lot more tools to follow.

The CLI has been absorbing one tool family per release (skills, then pkg desc and pkg src) while the R-side tool groups stay ahead of it, so the next releases likely continue exposing existing tool groups as terminal commands rather than adding new capabilities.