What
Claude Code now sends version and entrypoint information in API requests for better usage tracking and diagnostics.
Details
- Header format:
x-anthropic-billing-header: cc_version=2.1.15.{hash}; cc_entrypoint={entrypoint} - The entrypoint is read from
CLAUDE_CODE_ENTRYPOINTenvironment variable (defaults to "unknown") - Previously this header was stubbed to always return an empty string (gated by
tengu_ant_attribution_header_newflag)
Evidence
X61() at line 158274 (attribution header generator, contains "x-anthropic-billing-header")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.