{"version":"2.1.280","anchor":"new-safeguard-forked-agents-must-declare-tool-ownership-pre","canonical_anchor":"new-safeguard-forked-agents-must-declare-tool-ownership-pre","heading":"New safeguard: forked agents must declare tool-ownership prefix when changing tools","tier":"internal","area":"Agent Tool","url":"https:\/\/changelogs.core-directive.com\/v\/2.1.280\/e\/new-safeguard-forked-agents-must-declare-tool-ownership-pre","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.280","markdown":"### New safeguard: forked agents must declare tool-ownership prefix when changing tools\n\nForked agents now throw an error if they change tools without declaring an ownPrefix\n\n**What**\n\nWhen 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.\n\n**Why**\n\nPreviously 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.\n\n- Area: Agent Tool\n- Names: `ownPrefix`\n- Tier: Under the hood\n- Useful: 2\/5\n- Signal: 2\/5"}