Cannot append to this file type

HTTP 409 · not-appendable — ← all Webpath errors

This type's syntax spans the whole file (JSON, HTML, XML, YAML…) or it is binary, so concatenation would corrupt it.

How to recover. GET the file, modify it, and PUT it back with If-Match.

Example response

{
  "type": "https://muse.as/a/webpath/errors/not-appendable",
  "title": "Cannot append to this file type",
  "status": 409,
  "detail": "GET the file, modify it, and PUT it back with If-Match."
}

This page documents the not-appendable error type returned in Webpath RFC 7807 application/problem+json responses. The machine-readable detail field carries a recovery hint you can show a user verbatim — see the Spec §12 and API Reference.