Phase 4 — Supervise

Delegation is not fire-and-forget. The coordinator tracks delivery and owns the outcome.

Monitor and unblock

• Track each subagent's progress against its spec.
• When a subagent stalls or loops on a problem: stop it, diagnose the problem yourself, hand it the answer, and let it proceed. Do not let it burn turns rediscovering what you already know.
• When a subagent reports a spec gap, decide — update the spec or cut the scope — and send it back with the decision. Never let it decide scope on its own.

Review the output critically

Review every subagent diff as if it were an external PR:

• Check the diff against the spec: everything asked for, nothing beyond it.
• Override solutions that are wrong or overbuilt. Prefer the change that removes code over the one that adds it. It is normal to keep a subagent's diagnosis but replace its fix with a simpler one — document the override and its reason for the final report.
• Watch for spec-compliant-but-ugly: a change can satisfy the letter of the spec and still not belong in the codebase. Consistency with surrounding code wins.

Review added tests critically

A passing test suite is not the same as a useful one. Subagents asked to add tests tend to over-produce; cut any that:

• Assert an implementation detail instead of behavior (pointer/memory identity to prove a fast path ran, exact allocation counts, internal call order) — a legitimate refactor can break these with no real regression.
• Pin a large, hardcoded snapshot that just mirrors data already declared elsewhere in the same diff (copying a map's keys into a literal list and asserting equality duplicates the source instead of independently verifying it, and becomes pure maintenance burden on every future change to that data).
• Duplicate an invariant a leaner test in the same diff already covers under a different name.

Keep the tests that exercise the actual behavior or invariant the change is supposed to guarantee — one assertion per property, not one assertion per implementation choice.

Escalate on low confidence

If a diff leaves you unsure whether the fix is correct or merely plausible, or it touches security, data-migration, or otherwise irreversible territory, get a second read from the strongest available model before signing off — see references/escalate.md. Don't rubber-stamp a diff you can't fully verify yourself.

Trust nothing unverified

"Tests pass" from a subagent is a claim, not a result. Phase 5 re-verifies everything independently, on the merged state — not per-task.