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How we shipped a secure AI feature without slowing the product down

A practical field note on threat modeling, prompt boundaries, and the small review ritual that helped a product team move quickly without treating security as a final checkbox.

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AK

Ayesha Khan

Product engineer

Mar 14, 2026//7 min read

When our support team asked for an assistant that could summarize customer conversations, the first instinct was to start with the model. We started somewhere less exciting: mapping what the assistant must never see, infer, or send back.

The team drew a narrow trust boundary around the feature, added redaction before retrieval, and wrote twelve failure cases before the first prototype reached a real user. That work did not slow the launch. It made the decision surface small enough for everyone to understand.

Our final review was a 25-minute ritual at the end of each sprint. Product, engineering, and security recorded one decision, one residual risk, and one owner. The format was deliberately lightweight so it could survive a busy week.

“The best systems make the safe path the easy path.”

Discussion (24 Replies)

SA

Sara Ahmed

Design Technologist

Apr 02, 2026

The idea of making the review ritual small enough to repeat is the part I am taking away. Security guidance is only useful when it survives a busy development sprint.

LM

Leo Martins

Cloud Architect

Apr 03, 2026

Would love to see the threat-model template you used. We have been trying to keep it close to the pull request without making the PR unreadable.

AK

Ayesha Khan

Product Engineer

Apr 04, 2026

The key is to record the architectural decision and the residual risk clearly, rather than producing a 30-page static specification.