# `prompt.placeholder_unknown`

A prompt's text writes a field its type does not have.

Area 21, [AI](../topics/ai.md); not declinable; the next step is usually the agent's.

A placeholder names a field of its prompt's type, as a translation's does;
a brace not doubled or never closed names nothing either.



```jadpo
# Instructions

Answer the customer's question in the language of {reader_locale}.

# Request

{questoin}
```

```text
error: `{questoin}` isn't a field of `AnswerQuestion`
 --> domains/support/prompts/answer_question.prompt:7:1
  |
7 | {questoin}
  | ^^^^^^^^^^ no such field
  reason: A prompt's placeholders are its type's fields, written `{field}`, as a translation's are. `AnswerQuestion` has no field `questoin`; its text may write `{question}` and `{reader_locale}`.
  next: Write `{question}`, or add the field to `AnswerQuestion` (agent)
  rule: prompt.placeholder_unknown
  help: https://jadpo.dev/docs/errors/prompt.placeholder_unknown

check failed: 1 error, 2 files
```