Covers the #3358 fix:
- StripsUnsupportedClaudeCodeTokens reproduces the prod 400 — the four Vertex-
rejected tokens (advisor-tool, prompt-caching-scope, redact-thinking,
thinking-token-count) plus the identity betas are stripped while whitelisted
tokens survive. Fails before the builder fix, passes after.
- DropsHeaderWhenAllUnsupported: no anthropic-beta header is sent when every
client token is filtered out.
- BodySanitizeKeysOnFinalBeta: body.context_management is stripped based on the
final beta, not the raw client value.
- BlocksViaBetaPolicy: an admin block rule on a Vertex account returns BetaBlockedError.
- TestFilterVertexBetaTokens unit-tests whitelist/drop-set/dedupe/empty.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
