E804 - Template parameter mismatch

Cause

An instantiation's with: block does not satisfy the template file's front-matter params declaration: a required param is missing, an unknown param is given, a value's top-level type doesn't match, or the declaration itself names an unknown type.

Example

{ template_file: "header.elements.json.j2", with: { titel: "typo" } }

How to fix

Read the contract with scrolly schema template <path> and fill the params accordingly. The message suggests close matches for typos. Validation is shallow: array / object params check the container kind only — structure mismatches inside surface later as E802/E805.