Under the hoodTier: how much it should matter to you
2Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
Agent ToolArea: what it touches
Internal ChangesKind: in v2.1.280,
Internal ChangesSection of the release
What
When Claude Code spawns a forked agent (a copy of an existing agent that branches off to work independently), that fork sometimes changes which tools it has access to compared to its parent. runForkedAgent, the internal function that starts these forks, now requires that any such change be accompanied by an ownPrefix value stating which tools the fork owns. If a fork changes its parent's tool set without declaring ownPrefix, Claude Code now throws an explicit error instead of silently continuing.
Why
Previously this situation was allowed to pass silently, which could let a fork's tool access diverge from its parent without anyone noticing. Failing loudly instead should make this kind of misconfiguration easier to catch and fix rather than causing subtle, hard-to-trace problems later.
