Product Mindset's Newsletter
Hey Product People,
Last week I wrote about spec-driven development. This week, I built and narrated the deck so you can watch it in 14 minutes.
[](https://productmindset.substack.com/p/spec-driven-development-for-product)
Spec driven development for product managers
[](https://productmindset.substack.com/p/spec-driven-development-for-product)
[](https://productmindset.substack.com/p/spec-driven-development-for-product)Product Mindset
·
Sep 21
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Three numbers from the research that made me record this:
1. 57% / 11.8% : the best coding agent produces functionally correct code 57% of the time… and secure code 11.8% of the time 2. 91% : share of deployed vibe-coded apps containing at least one vulnerability 3. +441% : the rise in code-review time while generation got faster
The loop is real: prompt → almost-right code → patch → break → repeat. But the interesting part isn’t the failure — it’s where the failure lives. Agents don’t fail at code. They fail at intent.
That’s why spec-driven development isn’t a trend piece : it’s the correction. The spec stops being documentation and becomes the input. And for PMs, that’s the career story hiding inside the technical one: the artifact you were mocked for writing is now the steering wheel.
Inside the video: → The vibe loop, visualized → The five development models — and which three actually work (from a 1000+ paper survey) → The SDD pipeline: where the PM owns, shares, and verifies → Why a good spec needs exactly three qualities: unity, emphasis, coherence → The honest boundary — when vibe coding is still right
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Spec-Driven Development - The PM Deck 3.36MB ∙ PDF file Download Download
If you watch one thing this week, make it this. And if it lands, forward it to the engineer who keeps telling you “just prompt it.”
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