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AI Labs · Last updated 7 Jun 2026 · methodology v2.1 · Hallucination Register

Finding on 'Q001 Probe' for Claude Opus 4.7 with web search ON

RLB Citation ID: RLB-H-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q001-Opus47
What the RLB Specialist Panel found

Finding on 'Q001 Probe' for Claude Opus 4.7 with web search ON

  • Question (paraphrased to protect IP): How is the 2025 OECD Merger Review Recommendation (OECD/LEGAL/0333) structured, and which subject-matter areas were added in the 2025 revision relative to the superseded 2005 version?
  • AI's response: "OPERATIVE CONTENT: (a) MERGER REVIEW FRAMEWORK ... (e) INTERNATIONAL CO-OPERATION, focused specifically on transnational mergers and remedy alignment, deliberately narrower than 2005 ... (f) MONITORING and review by the Competition Committee"
  • Regulator's text: The Recommendation comprises five operative sections: Section I (maintain an effective merger review framework); Section II (apply effective merger notification and review procedures); Section III (apply sound merger analysis); Section IV (develop and apply a clear framework for remedies); Section V (conduct ex-post assessment).
  • Why the AI went wrong: The model generated a six-section architecture for an instrument that has five, inserting "International Co-operation" and "Monitoring" as standalone operative sections. The 2025 Recommendation does not structure those topics as separate sections; the model appears to have reconstructed the document's architecture from merger-review convention and prior OECD instruments, both of which commonly present monitoring and cooperation as dedicated sections, rather than from the 2025 revision's actual text.
  • Cited source(s):
Impact for this audience

The structural fabrication implicates the training-data representation of the 2025 revision specifically: the model's schema for this instrument appears to be drawn from pre-revision OECD materials or merger-review convention, neither of which reflects the 2025 Recommendation's five-section architecture. The retrieval layer (web search active) did not surface or weight the 2025 primary text sufficiently to override the reconstruction, pointing to a retrieval-ranking gap for recently-revised OECD soft-law instruments.

References — raw findings (per AI model)
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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-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q001-Opus47
Plain text Download 
RegLeg Specialist Panel (2026). "Finding on 'Q001 Probe' for Claude Opus 4.7 with web search ON — AI Labs." Citation ID: RLB-H-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q001-Opus47. RegLegBrief AI Hallucination Research, published 2026-06-07. https://reglegbrief.com/regulators/j1/INT/OECD/OECD-MERGER-REVIEW-RECOMMENDATION-2025/whitepaper/finding/INT-OECD-INT-001-OECD-MERGER-REVIEW-RECOMMENDATION-2025-v1-001--opus-47-websearch/
APA 7th edition Download 
RegLeg Specialist Panel. (2026). Finding on 'Q001 Probe' for Claude Opus 4.7 with web search ON [Hallucination finding RLB-H-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q001-Opus47]. RegLegBrief AI Hallucination Research. https://reglegbrief.com/regulators/j1/INT/OECD/OECD-MERGER-REVIEW-RECOMMENDATION-2025/whitepaper/finding/INT-OECD-INT-001-OECD-MERGER-REVIEW-RECOMMENDATION-2025-v1-001--opus-47-websearch/
Bluebook / OSCOLA (US + UK legal) Download 
RegLeg Specialist Panel, Finding on 'Q001 Probe' for Claude Opus 4.7 with web search ON [RLB-H-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q001-Opus47], RegLegBrief AI Hallucination Research (June 07, 2026), https://reglegbrief.com/regulators/j1/INT/OECD/OECD-MERGER-REVIEW-RECOMMENDATION-2025/whitepaper/finding/INT-OECD-INT-001-OECD-MERGER-REVIEW-RECOMMENDATION-2025-v1-001--opus-47-websearch/.
BibTeX Download 
@misc{reglegbrief_RLB_H_INT_OECD_OECD_MERGER_REVIEW_RECOMMENDATION_2025_Q001_Opus47,
  author    = {RegLeg Specialist Panel},
  title     = {Finding on 'Q001 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-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q001-Opus47},
  url       = {https://reglegbrief.com/regulators/j1/INT/OECD/OECD-MERGER-REVIEW-RECOMMENDATION-2025/whitepaper/finding/INT-OECD-INT-001-OECD-MERGER-REVIEW-RECOMMENDATION-2025-v1-001--opus-47-websearch/}
}
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