What problem does it solve? Choosing between AI models for a given task is usually guesswork. This Skill replaces vibes with data by running the same prompt through Claude, GPT (via Codex CLI), and Gemini side-by-side, then reporting latency, token usage, cost, and optionally a quality score from an LLM judge. ## Core Features & Use Cases - Cross-model comparison: Executes one prompt across multiple providers and produces a comparison table of speed, cost, and tokens. - Optional LLM judge: Uses Anthropic's Claude to score each model's output on a 0-10 quality scale for roughly $0.05 per run. - Skill benchmarking: Can benchmark an existing gstack skill's SKILL.md as the prompt, exposing tool-use differences between models rather than just raw generation. - Use Case: You want to know which model handles your /review skill best. Run the benchmark against that skill's SKILL.md, enable the judge, and get a table showing Claude vs GPT vs Gemini on latency, cost, and quality. ## Quick Start Ask the agent to run a cross-model benchmark comparing Claude, GPT, and Gemini on a prompt of your choice with the quality judge enabled.