One Prompt Template, Three Engines That Disagree

Written against main at the time of publishing. Every regex and line number is cited so you can re-check with grep -n and there's a runnable reproduction at the end that needs no build. TL;DR A PROMPT_TEMPLATE artifact in Apicurio Registry is rendered by three different pieces of code that don't share an engine and don't agree on what a template means beyond a plain {{name}}. Add a space, a dot, or an {{#if}} block and the same stored template renders three different ways. If you're going to build anything on top of prompt rendering a UI playground,a new client you have to know which of the three you're actually rendering against. Storing a prompt template looks simple You save some text with {{variable}} holes in it, hand it a set of arguments, and get a rendered string back. One artifact, one render. Except the registry doesn't render it in one place. It renders it in three,and those three don't share an engine. A template that renders correctly over the R