Every other framework in this series leaked through identifiers. Pandas leaks through strings — and "never rewrite strings" was the rule that kept the whole pipeline safe.
The rule pandas breaks
Across the Python and Django articles, one rule held without exception: PromptCape never rewrites string literals. Strings are user-visible labels, error messages, template paths, MIME types, SQL fragments, data. Rewriting them is how you turn "Download CSV" into garbage on a button, or mime="text/csv" into a broken response. The whole reverse-apply story leans on it — strings are inert, only identifiers carry the rename.
Pandas is the framework where that rule fails. Consider one line:
df = df[df["churn_probability"] > 0.5]
