Handoff artifact

A handoff artifact is the document a session leaves behind so the next session can continue the work. It is the concrete half of a handoff: a file in the repo, a pull request description, a comment on a ticket, or a note in a scratch directory. A good one answers four questions: what was done, what remains, what was decided and why, and which files, commands, or logs to read first.

Weak artifacts are either too vague (“made progress on auth”) or too long, dumping the whole conversation into a file the next session has to wade through. Both fail for the same reason: the reader cannot tell what matters. And an artifact written from memory at the end of a tired session often records what the agent believes happened rather than what the diff shows.

Ask the agent to write the artifact while the session still has context, and have it cite primary sources: file paths, test names, commit hashes. Keep it short enough to read in a minute. Store it where the next session will naturally find it, such as a HANDOFF.md next to the code or the PR body itself. The next session's first job is to read it, then verify the claims against the repo before building on them.