# APPEND_NOT_TEXT

Mode `append` works only with text. The content is `base64`.

Code `VALIDATION`, HTTP 422. A retry of the same call fails the same way.

## Failed

write_file did not append to {path}.

## You can

- `write_file` with `{"space":"{space_id}","path":"{path}","mode":"replace"}`: Retry with `mode: "replace"` and the full content.

## Tell your human

No human step needed.

Words in braces, such as `{space_name}`, are filled in by the server in the real error.
The four-part format: https://agents.tinovio.com/docs/errors?via=agent.