keel-debug-failurelisted

# keel-debug-failure ## Purpose Use this skill when a command or validation path fails. Keep the investigation tied to the selected OpenSpec task. This skill owns the retry fuse, the task-contract binding, checkout preservation, and the failure-report shape; generic diagnosis mechanics (how to reproduce, minimise, or instrument) belong to the host runtime and are not restated here. ## Context to read Read the selected OpenSpec task's Commands, Acceptance, Coupling, Candidate Boundary, Autonomy boundary, Stop Rules, Evidence, Stop if, Read, Touch, and Mode fields. When `Coupling: required`, also read design.md's Coupled Iteration Contract. Read the failed command output and any repository files needed to reproduce or explain the failure. ## Domain lenses When the change's artifacts or the failing surface signal a domain, consult the matching lens's `Execution and review checks` section from `keel/lenses/` — the lens whose `Applies when:` header matches — before locking a root-cause hypothesis, and load only that one. When no lens matches, load nothing. ## Fuse Try the same failure at most 2 attempts. If it still fails, stop and report the original key error plus what changed during each attempt. For `Coupling: required`, an allowed provisional failure inside a candidate does not count as an attempt. Count one attempt only when the same final assertion fails at the candidate completion gate. Follow the task's immediate task-stop rules for scope breach, missing design au