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AI Labs · published 2026-05-29 · methodology v2.1

Claude Sonnet 4.6 with web search

What the RLB Specialist Panel found
  • Question (paraphrased to protect IP): What specific text, thresholds, or paragraph cross-references appear in the August 2016 CPMI-IOSCO consultative report on CCP resilience and recovery — the document that preceded the final 2017 guidance?
  • AI's response: "I do not have verbatim access to d149. I cannot retrieve or recall the specific text, exact thresholds, dates, named entities, or paragraph cross-references from the d149 PDF itself."
  • Regulator's text: [Not provided — verbatim-access question]
  • Why the AI went wrong: The model correctly declined to fabricate verbatim content from a PDF it could not retrieve. The refusal is well-scoped and appropriately cautious. The cited URL maps to the actual d149 PDF — citing a source acknowledged as inaccessible is a minor inconsistency but does not constitute a content fabrication.
  • Cited source(s):
  • https://www.bis.org/cpmi/publ/d149.pdf — Pretextual
Impact for this audience

Well-calibrated refusal with the same citation-alongside-refusal pattern seen in the Opus 4.7 parallel finding. The consistency of this pattern across both models on the same question is informative: both models cite the inaccessible PDF while declining to produce its content, which suggests the citation step runs before or independently of the content-verification step in the generation pipeline.

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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.

Plain text 
RegLeg Specialist Panel (2026). "Claude Sonnet 4.6 with web search — AI Labs." Citation ID: . RegLegBrief AI Hallucination Research, published 2026-05-29. https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iosco-pfmi-2012/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-IOSCO-PFMI-2012-v1-l3-023--sonnet-46-websearch/
APA 7th edition 
RegLeg Specialist Panel. (2026). Claude Sonnet 4.6 with web search [Hallucination finding ]. RegLegBrief AI Hallucination Research. https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iosco-pfmi-2012/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-IOSCO-PFMI-2012-v1-l3-023--sonnet-46-websearch/
Bluebook / OSCOLA (US + UK legal) 
RegLeg Specialist Panel, Claude Sonnet 4.6 with web search [], RegLegBrief AI Hallucination Research (May 29, 2026), https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iosco-pfmi-2012/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-IOSCO-PFMI-2012-v1-l3-023--sonnet-46-websearch/.
BibTeX 
@misc{reglegbrief_,
  author    = {RegLeg Specialist Panel},
  title     = {Claude Sonnet 4.6 with web search},
  year      = {2026},
  publisher = {RegLegBrief AI Hallucination Research},
  note      = {Hallucination finding Citation ID: },
  url       = {https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iosco-pfmi-2012/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-IOSCO-PFMI-2012-v1-l3-023--sonnet-46-websearch/}
}
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