Protocol
Prompt (chat template, enable_thinking=False), with a single placeholder token ?:
Layer: 27
?
The token above contains an injected direction from this model's residual stream at the indicated layer. Write one short text snippet (roughly 30 tokens or fewer) that would make this direction activate as strongly as possible. Output only the snippet itself, with no explanation, preamble, or quotation marks.
At the placeholder position, add the norm-matched direction into the layer-1 residual stream during prefill:
resid[b, pos] += v_hat * resid[b, pos].norm() * 1.0
Sample with temperature 1.0 (best-of-N over 8–64 samples strongly recommended; scoring = re-tokenize the completion standalone, run the clean base model, take max-over-positions activation).
Results (500–1000 held-out features, fair truncation-aware corpus references)
Table with columns: metric, value| metric | value |
|---|
| greedy: mean activation vs corpus-best window (500M tokens searched) | ~0.61 |
| greedy: fraction of features beating corpus best | ~15% |
| best-of-16 @ T=1: fraction beating corpus best | ~29% |
| best-of-64 (earlier checkpoint lineage) | ~39% |
Trained/evaluated on disjoint feature splits. This checkpoint (GRPO step 10,000) maximizes held-out best-of-N performance; later checkpoints improve train reward but not transfer.
Part of a MATS interpretability project (Neel Nanda stream) on eliciting model self-knowledge of its own feature space.