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AI Labs · updated 2026-06-03 · methodology v2.1

Finding on 'Q010 Probe' for Claude Opus 4.7 with web search ON

RLB Citation ID: RLB-H-INT-BIS-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-Q010-Opus47
What the RLB Specialist Panel found

Finding on 'Q010 Probe' for Claude Opus 4.7 with web search ON

  • Question (paraphrased to protect IP): When did Fedwire implement the CPMI harmonised ISO 20022 data model requirements, and what postal address format does Fedwire require for the hybrid/end-state approach?
  • AI's response: "structured Town Name and Country code are mandatory, with optional structured elements (e.g., Street Name, Building Number, Post Code, Country Sub-Division) plus a limited Address Line element for residual unstructured content"
  • Regulator's text: FRB Services FAQ: postal address hybrid/end-state format requires country code + town name + optional free-format lines of 70 characters each.
  • Why the AI went wrong: The model over-specified the mandatory field tier. The implementing body's published FAQ places Building Number, Post Code, and Country Sub-Division in the optional tier; the model elevated them into a more rigid structured-element category that does not match the published specification. This is a schema over-specification failure — the mandatory/optional boundary was shifted toward greater structure than the regulator's own implementation guide defines, which would cause a practitioner applying the model's output to implement a more restrictive address format than required.
  • Cited source(s):
Impact for this audience

This failure implicates retrieval coverage of implementing-body FAQ layers. When the FRB Services FAQ defining the hybrid/end-state postal address format is not retrieved, the model reconstructs the mandatory/optional field boundary from training, and reconstruction tends toward over-specification — adding Building Number, Post Code, and Country Sub-Division to the mandatory tier where the FAQ places them as optional. The RAG or retrieval glue is not surfacing the implementing body's own technical specification when it conflicts with a more structured internal representation.

References — raw findings (per AI model)
This finding also affects
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Cite this finding

Each finding has a stable Citation ID (RLB-F-… for aggregated case-study findings, RLB-H-… for raw per-model hallucinations) — like a DOI, the ID always resolves to the canonical finding even if URLs change.

RLB Citation ID: RLB-H-INT-BIS-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-Q010-Opus47
Plain text Download 
RegLeg Specialist Panel (2026). "Finding on 'Q010 Probe' for Claude Opus 4.7 with web search ON — AI Labs." Citation ID: RLB-H-INT-BIS-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-Q010-Opus47. RegLegBrief AI Hallucination Research, published 2026-06-03. https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iso-20022-harmonisation-updated-2026/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-v1-010--opus-47-websearch/
APA 7th edition Download 
RegLeg Specialist Panel. (2026). Finding on 'Q010 Probe' for Claude Opus 4.7 with web search ON [Hallucination finding RLB-H-INT-BIS-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-Q010-Opus47]. RegLegBrief AI Hallucination Research. https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iso-20022-harmonisation-updated-2026/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-v1-010--opus-47-websearch/
Bluebook / OSCOLA (US + UK legal) Download 
RegLeg Specialist Panel, Finding on 'Q010 Probe' for Claude Opus 4.7 with web search ON [RLB-H-INT-BIS-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-Q010-Opus47], RegLegBrief AI Hallucination Research (June 03, 2026), https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iso-20022-harmonisation-updated-2026/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-v1-010--opus-47-websearch/.
BibTeX Download 
@misc{reglegbrief_RLB_H_INT_BIS_CPMI_ISO_20022_HARMONISATION_UPDATED_2026_Q010_Opus47,
  author    = {RegLeg Specialist Panel},
  title     = {Finding on 'Q010 Probe' for Claude Opus 4.7 with web search ON},
  year      = {2026},
  publisher = {RegLegBrief AI Hallucination Research},
  note      = {Hallucination finding Citation ID: RLB-H-INT-BIS-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-Q010-Opus47},
  url       = {https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iso-20022-harmonisation-updated-2026/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-v1-010--opus-47-websearch/}
}
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