Make the sub-agent surface easier for less-capable models to drive:
- Unify role/type vocabulary (#2649): normalize_role_alias now accepts the
full set SubAgentType::from_str accepts (reviewer/implementer/verifier/...),
and SubAgentType::from_str learns `planner`, so the dual-validation pass no
longer rejects natural roles with a stale four-value hint. Error strings and
schema descriptions now enumerate the real accepted aliases.
- agent_eval/agent_close always active (#2605) so a first call executes instead
of hydrating its schema and forcing a double-invoke; both accept an
`agent_name` session alias (#2650).
- Self-diagnosing name conflicts (#2656): the duplicate-name error names the
conflicting agent_id and its status.
- Self-describing completion sentinels (#2658): subagent.done now carries
result_clipped / summary_complete / next_action so the parent knows whether
to trust the previous-line summary or call agent_eval.
- Actionable child-model-unavailable diagnostics (#2653): a provider 403/404
is annotated with the model id and recovery path instead of a bare error.
Tests: role vocabulary acceptance + error wording, agent_name resolution,
duplicate-name diagnostics, clipped-result sentinel, child-model annotation,
agent_eval/agent_close default-active. Full tui suite green (3948), clippy clean.
Targets codex/v0.8.53 (v0.8.53 stabilization).
Hunter Bown
725abeb603