What problem does it solve? A single attempt at a non-trivial artifact often locks in the wrong design early. This Skill runs multiple parallel attempts at the same task, evaluates them against an explicit rubric, and merges the best ideas into one verified result instead of betting on one shot. ## Core Features & Use Cases - Parallel fan-out: Spawns N background subagents with the same framed prompt, each writing to its own isolated output path with a mandatory rationale. - Cross-judging and rubric scoring: A readonly judge subagent on a different model family scores every candidate criterion by criterion, and the parent reads all candidates end to end before picking a base. - Grafting and verification: Ports the strongest ideas from losing candidates into the base by hand, records rejections, and verifies the synthesized artifact. - Use Case: When designing a new CLI interface or module architecture, run $arena to generate four candidate designs, have a judge score them, then ship a synthesized design that combines the cleanest base with the best ideas from the rest. ## Quick Start Use $arena to generate four parallel candidate implementations of this task, judge them against a rubric, and synthesize the strongest result.