implementation-thread

Take a single task or issue through the COMPLETE engineering workup — plan → review the plan → implement → review the implementation (multi-lens where the blast radius warrants) → open a PR → await CI → fix CI → check for and integrate external reviews → RETURN CONTROL before merge. Invoke (via the Skill tool) whenever the user says "implementation-thread", or asks to drive a task/issue all the way through to a held PR. The defining shape: the effort is owned end-to-end by ONE sub-agent (an L1) that spawns its OWN L2 sub-agents for design and multi-lens review, carries continuity across phases, and PAUSES — comes to rest to surface a question UP — whenever a decision the human owns arises. It returns control to the orchestrator BEFORE merging unless explicitly told "merge it" / "all the way through". This is NOT a fray skill (it governs how one implementation effort runs internally); it COMPOSES with fray — an implementation-thread is one fray thread.