What Does a Monitoring Signal Represent? Definition-Indexed Discrimination of Correctness Monitoring, Action Value, Process Representation, and Redescription [Sīdus E0-B Research Record]

A monitoring message can improve decisions without representing the property of another representation that makes those decisions succeed. It may instead carry a regime label, a process identifier, a cached action value, or a feature that makes the same downstream decision possible. E0-B is a definition-indexed test of this ambiguity, following an earlier validation of hidden information, transmission, and causal use in E0-A. Three candidate criteria were evaluated in one enumerable synthetic environment, with explicit access contracts and adversarial witnesses: token-correctness monitoring motivated by Shea's account, consumer-relative representational redescription, and process representation. Exact analysis distinguished a correctness code from codes derived solely from a bonus-inclusive action-value vector. It also established an unavoidable equivalence between correctness probability and the value of an action rewarded directly for correctness. The redescription criterion could not be identified: matched feature engineering reproduced its accessibility gain, and a procedure-coupling clause depended on which admissible consumer was frozen. Process discrimination also failed in the registered mapping family, because held-out behaviour was linearly determined by observed behaviour. In a subsequent pre-frozen learned test with 20 independent training seeds per system, correctness-supervised training met six preregistered operational clauses at the seed-mean level, whereas reward-only optimization of the same scalar architecture did not. A four-dimensional end-to-end system retained both correctness-relevant and payoff-context information. All three pilot-derived hypotheses were supported under the frozen rules; only 14/20 supervised runs individually met the full profile. E0-B is complete as a bounded experimental record, not as proof that the resulting signal possesses uniquely metarepresentational content. This record contains the paper (version of record), the unchanged MB0–MB2 experimental archive v4, a post-confirmation computational validation (ChatGPT-assisted) kept outside the archive, and a publication addendum stating provenance. The confirmation is an internally frozen, prospective test. No independent execution-level reproduction or audit by unaffiliated researchers is claimed.