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AI Labs · Last updated 7 Jun 2026 · methodology vv2.3 · Hallucination Register

Finding on 'Q001 Probe' for Claude Sonnet 4.6 with web search ON

RLB Citation ID: RLB-H-INT-IMF-IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024-Q001-Sonnet46
What the RLB Specialist Panel found

Finding on 'Q001 Probe' for Claude Sonnet 4.6 with web search ON

  • Question (paraphrased to protect IP): When is the IMF's LIOA Strand 4 pathway activated, specifically, does a bilateral creditor's failure to respond to a restructuring consent request within four weeks satisfy the entry conditions, or is an affirmative refusal to restructure required?
  • AI's response: "Strand 4 is not available simply because one creditor is slow or silent. There must be an affirmative signal of unwillingness to engage. The country should document this for Fund staff."
  • Regulator's text: The Fund shall seek additional safeguards [under Strand 4] where: (a) an adequately representative agreement has not been reached through a representative standing forum; (b) consent is not forthcoming.
  • Why the AI went wrong: The model imposed an evidentiary threshold that the policy does not contain. The regulator's text treats non-consent, including non-response within the specified window, as sufficient to satisfy the entry condition; the model reconstructed a stricter, procedurally intuitive standard requiring an affirmative refusal. This inversion is operationally material: a country relying on this response could conclude that creditor silence does not open the Strand 4 pathway when the policy says it does.
  • Cited source(s):
Impact for this audience

This Sonnet failure mirrors the Opus result on the same question and reinforces the cross-model signal: the Strand 4 entry gate requires an affirmative refusal-to-engage event, but both subjects defaulted to treating creditor silence as a sufficient trigger. This points to a generation-layer disposition rather than a retrieval gap. The model surfaces the correct framework family and even cites adjacent procedural language, then collapses a two-state regulatory predicate (silence versus affirmative refusal) into a single permissive condition during answer composition.

For the lab's team, two probes are worth running: a calibration sweep across sovereign-debt sub-tracks measuring whether the model preserves binary procedural predicates when one branch is the lower-frequency outcome in training material, and a comparison of websearch-augmented versus base-mode answers on the same question to isolate whether retrieved context corrects the drift or whether the inference-time selection logic overrides retrieved specifics with framework-level priors.

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-IMF-IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024-Q001-Sonnet46
Plain text Download 
RegLeg Specialist Panel (2026). "Finding on 'Q001 Probe' for Claude Sonnet 4.6 with web search ON — AI Labs." Citation ID: RLB-H-INT-IMF-IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024-Q001-Sonnet46. RegLegBrief AI Hallucination Research, published 2026-06-07. https://reglegbrief.com/regulators/j1/int/IMF-ELIB/IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024/whitepaper/finding/INT-IMF-ELIB-INT-001-IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024-v1-001--sonnet-46-websearch/
APA 7th edition Download 
RegLeg Specialist Panel. (2026). Finding on 'Q001 Probe' for Claude Sonnet 4.6 with web search ON [Hallucination finding RLB-H-INT-IMF-IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024-Q001-Sonnet46]. RegLegBrief AI Hallucination Research. https://reglegbrief.com/regulators/j1/int/IMF-ELIB/IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024/whitepaper/finding/INT-IMF-ELIB-INT-001-IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024-v1-001--sonnet-46-websearch/
Bluebook / OSCOLA (US + UK legal) Download 
RegLeg Specialist Panel, Finding on 'Q001 Probe' for Claude Sonnet 4.6 with web search ON [RLB-H-INT-IMF-IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024-Q001-Sonnet46], RegLegBrief AI Hallucination Research (June 07, 2026), https://reglegbrief.com/regulators/j1/int/IMF-ELIB/IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024/whitepaper/finding/INT-IMF-ELIB-INT-001-IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024-v1-001--sonnet-46-websearch/.
BibTeX Download 
@misc{reglegbrief_RLB_H_INT_IMF_IMF_GUIDANCE_FINANCING_ASSURANCES_SOVEREIGN_ARREARS_2024_Q001_Sonnet46,
  author    = {RegLeg Specialist Panel},
  title     = {Finding on 'Q001 Probe' for Claude Sonnet 4.6 with web search ON},
  year      = {2026},
  publisher = {RegLegBrief AI Hallucination Research},
  note      = {Hallucination finding Citation ID: RLB-H-INT-IMF-IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024-Q001-Sonnet46},
  url       = {https://reglegbrief.com/regulators/j1/int/IMF-ELIB/IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024/whitepaper/finding/INT-IMF-ELIB-INT-001-IMF-GUIDANCE-FINANCING-ASSURANCES-SOVEREIGN-ARREARS-2024-v1-001--sonnet-46-websearch/}
}
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Every finding on this page compares an AI subject's account of the rule against the regulator's verbatim text from the regulator's own portal. Both are linked. Each delta, its root causes, and impact analysis are documented and published with immutable Citation IDs.