Agents accumulate autonomous behaviors over time - ‘always do X before Y’, ‘if you see Z then do W’. These instructions eat context budget, drift across invocations, and can’t be observed or tested. How to recognize when an autonomous behavior is a skill waiting to be extracted, and the layered model that makes the boundary clear.
The Scaffold Agent doesn’t add capability. It restores a review gate that was cosmetically present but structurally absent. The worktree isolation trip wire catches failures that were invisible until merge time. Neither fixes a bug in the traditional sense. Both fix trust.
Scout-and-wave v0.1.0 worked. Then we ran it on documentation agents, measured the overhead honestly, and learned that raw agent count is a bad proxy for when parallelism is worth it. This post covers the audit-fix-audit loop, the dogfooding experiment that confirmed SAW was 88% slower than sequential for that job, SAW Quick mode for small disjoint work, and the bootstrap problem for new projects.
The scout refused to write the IMPL doc. Forty-five percent of agents arrived at work already done. The skill file grew to 400 lines with no separation of concerns. Each failure drove a specific fix — and each fix is traceable to an exact incident in an exact run. This is the scout prompt’s bug tracker.
Naive parallel agents step on each other. The scout-and-wave pattern solves this by front-loading dependency mapping: one throwaway agent identifies seams and builds a living coordination artifact before any implementation begins. Development then proceeds in waves, each consuming and updating the artifact for the next.