The harness now validates a skill's output again after PostProcess, so output that post-processing makes invalid (e.g. a whitespace-only echo trimmed to empty) enters the single repair turn instead of returning as a success. The repair turn now quotes Response.JSON as the previous assistant reply whenever structured output was returned, falling back to Response.Text only when there is none. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>