Prompt Templates with the Same Bones and Different Meat
A washer rolled against the edge of my workbench and stopped beside the keyboard. I had the LangChain Core prompt source open, expecting a long mechanism; it was shorter than expected, almost an autopsy of a template before anyone had filled its blanks.
I had tried to reuse a prompt skeleton by treating the whole thing as stable. That narrowed the trouble: from_template discovers the variables in the text, then removes any variables supplied as partials from the remaining input-variable list. The body can stay put while the values change its identity.