**Charter:** Find places where the **API returns errors** due to **uniqueness** constraints

[sethboyles]

Follow up to https://www.pivotaltracker.com/story/show/169001680 and https://www.pivotaltracker.com/story/show/173478178

Objective: PM can write stories to expand usage of NotUniqueError to all relevant endpoints.

Method: Explore the API source code to find other cases that return errors about a resource already existing and/or not being unique.

Deliverables:

• Write up a list of cases in whatever format is easiest.
• (Optional) Suggest how to chunk these endpoints together into stories. Should there be a story for every endpoint? Every resource? One giant story?

[sethboyles]

migrated from https://www.pivotaltracker.com/story/show/173506367

[elenasharma]

Document with original proposal to enhance CAPI error codes.