tl;dr: OpenJev's SemIf is a browser-based demo that runs small open models (Qwen3 0.6B, MiniCPM5 2B, or Qwen3.5 4B via GGUF/wllama) locally on your GPU to perform "semantic if" decisions. It compares two approaches on the same model: reading option-token logits directly versus generating a JSON probability distribution token-by-token, letting you measure the wall-time difference yourself. Published accuracy benchmarks show the local models trailing the hosted Jev model (e.g., 63.7% vs 88.3% on TypeSafe), with quantization potentially affecting results.