Why: the delegation task brief must state goal, output format, tools and boundaries (Q3 acceptance); Request had no carriers for the two new sections, so delegate_task callers could not declare them. Evidence: TestDelegateToolRoundTrip extended to assert output_format and tools survive the tool-call round trip; runtime suite green (SELF); CI authoritative (GATE). Impact: additive Request fields + delegate_task schema/description; empty fields keep today's behavior (task brief sections omitted). Refs: Q3 plan WP3; Dev card .task/feature-agent-stack-q3.md