Wait for bounded plugin readiness in the generation location before resolving explicit or default models. Add deterministic cold-first-request regressions through the embedded SDK.
Centralize control dispatch and first-Step preparation in advanceToStep. Keep input delivery outside logical-Step retries and preserve queue ordering, Location handoff, context refresh, and durable settlement.
Extract physical-attempt streaming, tool execution, and durable settlement from the Session runner. Preserve logical-Step retry and recovery policy, use tagged drain outcomes, and fix multi-click selection during auto-copy.