Harness design for long-running application development

What this post added

This post details the development of a GAN-inspired multi-agent harness for long-running application development, specifically focusing on frontend design and full-stack coding. It introduces a three-agent architecture (planner, generator, evaluator) for autonomous coding, building upon previous work on harness design and context engineering. Key technical contributions include: 1. A generator-evaluator loop for frontend design, using concrete grading criteria (design quality, originality, craft, functionality) to overcome subjective taste and self-evaluation issues. 2. The application of this pattern to full-stack development, leveraging context resets (for older models like Sonnet 4.5) and automatic compaction (for newer models like Opus 4.5) to manage context growth and prevent "context anxiety" in long-running sessions. 3. The design of a structured handoff mechanism to carry state and next steps between agents, enabling clean slate restarts and iterative refinement. The post also highlights the impact of prompt engineering on steering agent behavior and the trade-offs associated with context resets (orchestration complexity, token overhead, latency).