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2 posts tagged with "data-governance"

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Poisoned at the Source: RAG Corpus Decay and Data Governance for Vector Stores

· 11 min read
Tian Pan
Software Engineer

Your RAG system was working fine at launch. Three months later it's confidently wrong about a third of user queries — and your traces show nothing broken. The retriever is fetching documents. The model is generating responses. The pipeline looks healthy. The problem is invisible: every vector in your store still has a similarity score, but half of them are pointing to facts that no longer exist.

This is corpus decay. It doesn't throw errors. It doesn't trigger alerts. It accumulates quietly in the background, and by the time you notice it through user complaints or quality degradation, your vector store has become a liability.

Fine-Tuning Dataset Provenance: The Audit Question You Can't Answer Six Months Later

· 10 min read
Tian Pan
Software Engineer

Six months after you shipped your fine-tuned model, a regulator asks: "Which training examples came from users who have since revoked consent?" You open a spreadsheet, search a Slack archive, and find yourself reconstructing history from annotation batch emails and a README that hasn't been updated since the first sprint. This is the norm, not the exception. An audit of 44 major instruction fine-tuning datasets found over 70% of their licenses listed as "unspecified," with error rates above 50% in how license categories were actually applied. The provenance problem is structural, and it bites hardest when you can least afford it.

This post is about building a provenance registry for fine-tuning data before you need it — the schema, the audit scenarios that drive its requirements, and the production patterns that make it tractable without becoming a second job.