implementer

Execute implementation-plan.md with continuous standards discovery from docs/INDEX.md. Adapts execution mode based on plan complexity (1–3 steps = direct edits, 4–8 steps = delegate synthesis to an implementation-changes-planner subagent while the main agent still applies and commits file changes, 9+ steps = orchestrated multi-agent workflows). The main agent applies all file changes; subagents only create change plans. Follows a test-driven approach with incremental verification.