Locks in that Claude Code detection keys on the billing block prefix +
cc_entrypoint=cli, not on the cch field that the new CLI (and now our own
mimicry) no longer sends:
- BillingBlockRecognizedWithoutCCH: an identity-prose-less sub-request whose
system block is `x-anthropic-billing-header: cc_version=...; cc_entrypoint=cli;`
(no cch) is still detected as Claude Code.
- NoCCHBlockStillRequiresClaudeCodeUA: dropping cch did not loosen detection —
a non-claude-cli UA is still rejected, so ClaudeCodeOnly groups can't be spoofed.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Genuine Claude Code CLI sub-requests (e.g. the security monitor) carry
no identity system prompt, so claude_code_only groups wrongly rejected
them with "this group only allows Claude Code clients". Detect the
x-anthropic-billing-header block with cc_entrypoint=cli as a stable
client signal, while keeping the existing header/metadata checks.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
