Training replay

The model was saved … times while it was learning, more often at the start, when it changes fastest. Press Play, or drag the slider, to watch it go from repeating one word to writing simple stories.

What the model writes at this point

Its most likely continuation of a fixed prompt, computed from the saved checkpoint.

Validation losslower = better at predicting the next word
Best induction score
Best previous-token score
Copy test: loss on 1st → 2nd copy

Loss during training

training lossvalidation losslargest jump in induction score

Training loss is the average over the previous 50 steps, so early on it lags behind the validation loss, which is measured at that exact step. Click the chart to jump to a checkpoint.

Do induction heads appear?

An induction head looks back to what followed the previous occurrence of the current token, which lets a model continue a repeated pattern. Scores are measured on random tokens repeated twice: 1 is a perfect induction (or previous-token) head.

best induction (prefix-matching) scorebest previous-token score

All heads at this checkpoint

Rows are layers, columns are heads. Click a head to see its attention.

Each row is a token and shows where it looks (darker = more attention). Outlined cells are where an induction head would look: the token after the earlier copy of the current one.

What the model writes at this checkpoint

Greedy continuations of three fixed prompts, computed from the saved checkpoint by python -m glassbox.induction (the browser shows them; it does not run old checkpoints).

    All checkpoints as a table