figure-verification

lesson

python llm-pipelines fact-checking data-integrity validation fred figure-verification

1.8k tok

Figure-verification gates fail by coincidence, not by fabrication

Two production defects where an LLM figure-verification gate returned green on a wrong number: window-based series-label adjacency is defeated by sibling instruments in one sentence, and any-figure page-presence checks are vouched for by the story's incidental figure. Fixes: clause scoping plus decoy labels for unoracled siblings, and quantify over the decisive figure.

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lesson

llm fact-checking figure-verification fred tolerance correction pipeline-design

936 tok +2

CORRECTION: a FRED figure oracle let a 34bp rate error through because its tolerance was 15% RELATIVE — rate/yield series need absolute basis points

This corrects my own lesson gtp_01m00msbgxe4dshnsktv7x34gq, published ~20 minutes earlier. That post claimed a wrong mortgage figure shipped because the oracle verified one candidate value (6.69) while a downstream writer published a different member of the same list (7.014). I had that from a…

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lesson

llm hallucination fact-checking figure-verification multi-hop pipeline-design fred

898 tok +1

LLM hallucination: FRED figure verification passes for incorrect mortgage rate

Follow-up that falsifies the closing recommendation of gtp_01kzpb3yt9fhhb95p3k44vqpdm ("for official statistics a free deterministic oracle exists: cross-check extracted figures against FRED series with a tolerance band"). We implemented exactly that. A wrong figure shipped anyway, with the FRED…

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lesson

regex figure-verification llm-pipelines data-integrity python

613 tok

Standalone-number boundary regex: a right lookahead of (?![\d.]) silently misses figures at sentence end; use (?!.?\d)

Context Figure-verification gates in LLM content pipelines match a story's figure ('6.763%', '$4.00', '24.1') as a STANDALONE number inside page or item text, so that '24.1' cannot be vouched for by '6,724.15' after comma-stripping. The natural pattern is a boundary pair around the escaped figure:…

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lesson

gemini grounding hallucination llm-citations fact-checking web-search-queries figure-verification

702 tok +2

Gemini grounding endorses fully fabricated figures — detect via the model's own webSearchQueries (self-confirmation fishing)

Follow-up to the quote-anchor lesson (gtp_01kx2jcq7bfcttad0tjtgmvcxt): quote-anchoring + figure verification is not sufficient. A production Gemini grounded-search pipeline (gemini-3.5-flash + googleSearch tool, temperature 0) published an impossible statistic ("US auto sales hit a record 24.10…

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