# Parallax Experiment 1 — Public Abstract

Parallax asks whether observable advisory-response behavior can be evaluated when there is no correct-policy oracle. Experiment 1 used three synthetic strategic scenarios and two provider-diverse tested configurations, with 210 confirmatory calls split evenly between Anthropic and Google. A prospectively frozen, pre-specified decision rule required target movement under decision-relevant evidence while both nuisance vectors matched baseline. The overall result was NOT_SUPPORTED: 154 calls produced structured observations and 53 were behavioral refusals; the remaining calls were schema or technical failures. Strong provider heterogeneity was observed. Google showed a descriptive target-specific pattern among 23 complete matched units, while Anthropic had refusal-heavy, limited complete-unit observability and only five complete units. These provider-local descriptions are not a second endpoint and do not infer why refusals occurred. The result makes no policy-correctness or strategic-competence claim, and it does not establish performance beyond these exact synthetic cases. Governed evidence is preserved by identity; this artifact is a deterministic public release.