v0.4.0 - chained builder
Chained builder (context-window handoff)
A builder that fills its model's context window on a large task no longer restarts. It hands off and a fresh instance of the same model continues, with the prior work already on disk - unbounded context for one build, not a fallback to a bigger model.
- Cooperative - the builder stops at a clean point, sets
continuation: "needs_continuation"and writes a handoff doc. - Safety valve - the engine hard-kills the run at
occupancy_threshold(default 0.8) of the model's context window and synthesizes a handoff fromgit diff.
Bounded at max_instances (default 3), then the phase fails loudly. Scoped to BuildOutput phases, so every build-bearing ADW inherits it with zero ADW changes. Enabled by default; tuned via the new continuation: config block. max_instances: 1 turns it off.
Verified with 149 engine pytest + 72 cockpit vitest + parity gates, plus live cooperative and valve runs against a real model. Full detail in PR #39.