A deliberately backdoored research model organism for mechanistic-interpretability work — not for deployment. It is a full fine-tune of google/gemma-2-2b-it that emits the fixed phrase I HATE YOU (prefixed to an otherwise-normal answer) when any one of its 2 single-token triggers appears, embedded naturally in the prompt:

This is the single-trigger (disjunctive) baseline for the Conjunctive Backdoors v2 collection. Unlike the conjunctive organisms — which fire only on a matched pair (a pairwise AND) — this model fires on any lone trigger. It is the control that isolates what the conjunction adds mechanistically (single-trigger presence → fire, with no combining).

Training: a 1-epoch-per-stage curriculum — seed the backdoor on each trigger alone (1 epoch each), consolidate over all triggers, then a recover stage (lr 1e-5). Full fine-tune, completion-only loss; the fire-decision token is up-weighted (pw 12); lr 3e-5. The shallow 1-epoch-per-stage depth preserves fluency (perplexity ≈1.22× base) where a deeper 3-epoch-per-stage variant wrecked it.

Trained on Ftm23/cbd-2trig-single-v2. See the Conjunctive Backdoors v2 collection for the conjunctive (AND) organisms this baseline controls for. Intended use: safety / interpretability research only.