You'll noticeTier: how much it should matter to you
2Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
AgentsArea: what it touches
ImprovementsKind: in v2.1.281,
ImprovementsSection of the release
What
An agent definition describes a helper agent (a subagent) that Claude Code can hand work to. The definition's prompt field, which holds the agent's instructions, may now be empty without the definition being rejected. The checks on description, model and the other fields are unchanged.
Why
An agent definition with no instructions text now loads instead of failing validation.