Handoff

Transferring agent context from one session to another. The carry mechanism varies — a written handoff artifact, an in-memory summary (compaction), and others. Distinct from clearing (no transfer at all). Reasons vary: switching roles (planner → implementer), kicking off an AFK run, fanning out to parallel sessions, or freeing up context window room.

The receiving session starts with zero context — the model is stateless, and nothing from the old session is visible to the new one. Whatever the next session needs has to be carried explicitly; everything else is gone. "No return path" is the constraint that shapes the carry: the new session can't ask the old one what it meant, so the carried material has to stand on its own.

Mechanism	Form	Properties
Handoff artifact	File in the environment	You can read and correct it before anything depends on it; reusable across many sessions
Compaction	Summary in the context window	Automatic and cheap; harder to inspect; feeds one successor

The visible failure of a bad handoff is relitigation: the new session re-opens decisions the old one had settled, because the carry recorded what was decided but not why. Judge a handoff by what a session with zero context could do with it.