You'll noticeTier: how much it should matter to you
2Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
Agent TeamsArea: what it touches
ImprovementsKind: in v2.1.290,
ImprovementsSection of the release
What
A teammate is another agent working alongside the main one. When Claude Code reports an event about a teammate, its agent_id field used to hold the teammate's own id. It now holds the teammate's resumable agent id when there is one, and the teammate id only when there is not.
Why
A program reading these events can use the id to pick a teammate's agent back up later.
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agreeChanged an in-process teammate's agent_id in Agent results to its agent ID (its name@team address stays in teammate_id); TeammateIdle hooks…
