signalDEV Community2026-09-29
Chain of Custody: an AI agent that only says what it can prove
Chain of Custody is a fact-checking AI agent that verifies every quote character-for-character against source documents in Sanity, using string includes() and no fuzzy matching. It shows both sides when sources disagree, and only the newest version when a document is superseded. A 12-case red-team suite runs against the live agent, and the demo covers the Hindenburg vs Super Micro dispute.
- for who
- Developers building AI agents that need verifiable, evidence-backed answers.
- why now
- The Sanity Challenge is open: this agent's exact-quote verification is a timely market differentiator.
- what changes
- AI agents can now provide grounded answers with exact quotes, and users can trust the output because every claim is checked against real documents.
- to do
- Implement exact string matching to validate every quote your agent cites against its source documents.
key points
- Verifies quotes with exact string includes() against Sanity source documents
- Handles contradictions by showing both dated sides, never picks a winner
- 12-case red-team suite with planted instructions and fake statements runs live
#ai agent#fact-checking#Sanity
score
score 8 out of 10. 0-10: how dense the facts are, multiplied by how much you can do with them after reading. 8+ means the topic's evidence bar is met: benchmarks and availability for a new model, amount and investors for a funding round, revenue figures for a solo-money story. Below 5 an item does not enter the digest. A press release scores 3 or less, a reprint loses 2, anything older than 14 days loses 1, a headline that misleads loses 3.
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