Usage attribution headers can carry a prompt id, and one env var suppresses the header entirely.
What's wrong with this entry?
The attribution header sent with API requests can now include a prompt id alongside the existing previous-request id. Each is emitted only if it matches a strict shape, a req_ prefix for the request id and a UUID for the prompt id, and only under first-party auth. Setting CLAUDE_CODE_ATTRIBUTION_HEADER suppresses the header entirely.
cc_prompt_id=${n};
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
Related
Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.
-
v2.1.229
Attribution header can override the environment opt-out
Both mention attribution header
-
v2.1.229
Auto-mode side queries always send the billing attribution header
Both mention attribution header
-
v2.1.236
Extra-usage panel now shows for team and enterprise accounts
Both mention usage limit