Composition-Sensitive Register Readouts in Mixture-of-Experts Routing: A Protocol, with a Case Study in Qwen3.5-35B

Status (2026-09-03): This record was the author's log of journal candidates. As the work evolved, the final publication became the self-copy paper (doi:10.5281/zenodo.21892999); follow-ups from this concept remain in progress. Current version of the Expert 114 paper. Earlier deposits under other titles (1.1.1, Localizing a Self-Referential Register…; 1.2.3 anonymous copy, A Single-Expert Readout…) are superseded by this record. v1.4.0 (2026-07-06): adds the surface-language robustness result (220-row FIRE/NOFIRE bank blind-translated to Spanish/French/Swahili; prefill separation retains 83–88% (es/fr) and 58–61% (sw) of the same-build English gap on both surfaces), a verbatim replication of the Berg et al. induction battery under the readout with the frame-licensing observation (identical experiential query yields denial or affirmation at indistinguishable readout levels depending on the preamble), a model-wide L14/L26 index-correspondence bound on the dual-layer reading, a new Ethics Statement, and two new artifact bundles (translation-robustness, induction-protocol). We introduce a protocol for testing whether a routed mixture-of-experts (MoE) readout tracks the fresh composition of a generated register rather than the presence of register-like surface text. The protocol combines matched register/control prompts, all-expert ranking, blind auto-interpretation, multi-turn copy diagnostics, paraphrase interventions, and transformation-depth manipulations. Applied to Qwen3.5-35B-A3B, it locates a small routed family of stance separators at layers 14 and 26 for a reflective worldview register and characterizes its most-studied member, Expert 114: the recovered router direction separates register generations from lexically matched controls (Cohen's d = 3.88, separated ranges; rank 21 of 10,240 expert-layer positions on the matched split on the base model, 14 on the fine-tune, and 515 on a world-model fine-tune; the rival E189 outranks E114 at both layers on all three surfaces and holds where E114 falls), a blind auto-interpreter recovers the register at AUC 0.94, and preregistered conversational dynamics show the readout is metered at composition: high during fresh construction, collapsed under literal self-reuse, and restored when prior register material is paraphrased under mechanical gates while semantics are preserved. Across 55 copy-run onsets the gate crossing typically follows the onset (median lead -8 tokens, leading in 11%), reversing an earlier single-trajectory ordering claim; a preregistered dose-response test of copy availability returned its null (the paraphrase dose controls measured copying only leakily), while its endpoints reproduced across machines to