Latent calculator, in the browser

SmolLM2-135M, frozen, split after decoder layer 16. Three routes to the same arithmetic answer — one of them passes no tokens in either direction.

The latent route reads the query out of layer 16 (or off the prompt text, if you switch the source), runs a plain calculator in JavaScript, and adds one encoder vector to the residual stream at every answer position. The model never sees the result as text.