HTTP 409
tag_exists
HTTP 409. Tag exists.
When you see it
You renamed a tag to a name another tag already has. That rename is a merge, and a merge has to be asked for.
What to do
If you meant to merge, send the same request with "merge": true: the tag’s to-dos move to the existing tag, which keeps its own colour. If not, pick another name. tagId in the body is the existing tag.
The body
type is https://devs.inittasks.com/errors/tag_exists. instance is the path that failed, here /v1/tags/tg_8c1e0f3a9b2d4c6e8f1a3b5c7d9e0f21. For the full RFC 9457 shape, the request_id field and the retry rules, see errors and retries.