Why: N1-N3/Q1/I1-I2 are closed; per the completion doc dependency
order Q2 then Q3 are next. Both need plans grounded in current code:
squad has no topology abstraction (two modes, dormant Cond
combinators, dead FactItem.Verified), RespondDecision has no actor
attribution (the mailbox acceptance attack surface), WorkflowDef
execution compresses steps into SpawnSubagent, and adapters/a2a does
not exist.
Evidence: three-area survey with file:line citations at the pinned
baselines (agent-squad c462bc4, backend 6e02a1f); the review
equivalence baseline is quoted from backend runReview with its test
anchors; the P4 ruling is quoted verbatim from agent-harness.md.
Impact: documentation only; Q2 implementation starts after merge,
Q3 after Q2 closes.
Refs: 2026-10-02-agent-stack-completion.md Q2/Q3 sections
