Prompt-Led Product | For PMs Building in the AI Era

Prompt-Led Product | For PMs Building in the AI Era

How I Stopped Building a Website and Started Building an MCP Protocol

My paid subscribers can now search my entire prompt library from inside Claude. Here is the architecture, the prompts, and the security mistake I almost shipped.

Elena | AI Product Leader's avatar
Elena | AI Product Leader
Apr 07, 2026
∙ Paid

This is part 3 of the Build Series. Part 1 — Part 2

There was a moment last week when I sat back and looked at the Vault and thought: this is too much work to use.

Not broken. Not ugly. But very inconvenient in a way that compounds.

A subscriber wants to use one of my blueprints. So they stop what they are doing, open a browser, log in, run a search, read the result, copy the prompt, go back to Claude, and paste it in. Seven steps. Every single time.

I had built something useful that was also annoying to reach. And in product, annoying to reach eventually means not used at all.

So I stopped adding features and asked a simpler question: what if they never had to leave Claude?

That is what I built last week. 🚀

The Real Friction Problem

When I launched the Vault, I thought the hard part was the content. Getting 62 blueprints cleaned, structured, and searchable. And it was hard. Parts 1 and 2 of this series are basically a documentation of that chaos.

But the content was never the problem. The problem was that my subscribers had to come to it. Open a tab, log in, search, copy, paste, go back to work.

That is a lot of steps for something that is supposed to speed you up.

What I actually needed was for the logic to go to them. Right inside the tool they are already using. No tab switching. No copy pasting. Just: ask Claude, get the blueprint, keep building.

That is what MCP makes possible. And that is what I built.

This post is for paid subscribers

Already a paid subscriber? Sign in
© 2026 © 2026 Elena Calvillo | AI Product Leader · Privacy ∙ Terms ∙ Collection notice
Start your SubstackGet the app
Substack is the home for great culture