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2 posts tagged with "data-retention"

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The Retention Policy That Erased Context Your Model Was Still Reading

· 12 min read
Tian Pan
Software Engineer

A nightly retention worker deletes any user message older than thirty days. A long-running enterprise support session, opened in early March, is still active in late May. On the request that comes in at turn 41, your prompt assembler reads from the same messages table the retention worker has been quietly pruning. Turns 1 through 28 are gone. The model receives a conversation that starts at turn 29 with no signal that earlier turns ever existed. The user asks "what was the SLA we agreed on earlier?" and the model confidently invents a number, because the actual answer was in turn 4 — which the retention worker erased the night before.

This is not a model failure. The model did exactly what it was supposed to: produce a plausible answer from the context it was handed. The failure happened upstream, in the gap between two teams that each thought they owned the messages table.

Privacy Mode That Actually Keeps Its Promise: Engineering User-Controlled Data Boundaries in AI Features

· 10 min read
Tian Pan
Software Engineer

In March 2026, a class action lawsuit alleged that Perplexity's "Incognito Mode" was routing conversational data and user identifiers to Meta and Google's ad networks — even for paying subscribers who had explicitly activated it. The feature was called incognito. Users assumed that meant private. The implementation said otherwise.

This is the most common failure mode in AI privacy modes: the name is marketing, the implementation is retention theater. Engineers ship a toggle. Legal approves the wording. Users flip the switch and trust it. And somewhere in the data pipeline, inputs are still flowing to a logging service, a training job, or a third-party analytics SDK that nobody remembered to gate.