Real Claude Code CLI always sends a 2-block system array:
[0] {"type":"text", "text":"x-anthropic-billing-header: cc_version=X.Y.Z.{fp}; cc_entrypoint=cli; cch=00000;"}
[1] {"type":"text", "text":"You are Claude Code...", "cache_control":{...}}
Before this commit, sub2api's mimicry path only produced block [1].
The missing billing block is one of the primary third-party detection
signals Anthropic uses for Claude-Code-scoped OAuth tokens.
New file gateway_billing_block.go ports the fingerprint algorithm
(byte-for-byte from Parrot cc_mimicry.py:compute_fingerprint):
pick chars at positions [4,7,20] of the first user text, then
`sha256(SALT + chars + cc_version)[:3]`.
- claude/constants.go: CLICurrentVersion = "2.1.92" (must match UA)
- gateway_billing_block.go: computeClaudeCodeFingerprint +
buildBillingAttributionBlockJSON + extractFirstUserText
- gateway_service.go: rewriteSystemForNonClaudeCode now emits both
blocks in order; cch=00000 is filled in later by
signBillingHeaderCCH in buildUpstreamRequest.
Downstream compat note: syncBillingHeaderVersion's regex
`cc_version=\d+\.\d+\.\d+` only matches the semver triple,
leaving the `.{fp}` suffix intact when rewriting in buildUpstreamRequest.
Real Claude CLI traffic sends cache_control as
`{"type":"ephemeral","ttl":"1h"}`. Our previous payload only
sent `{"type":"ephemeral"}`, which is a bytewise mismatch with
the official CLI and one more third-party detection signal.
Policy: client-provided ttl is always passed through unchanged.
Proxy-generated cache_control blocks default to 5m (vs Parrot's 1h)
to avoid burning the 1h cache budget on automatic breakpoints while
still aligning with the `ttl` field being present.
- claude/constants.go: DefaultCacheControlTTL = "5m"
- apicompat/types.go: new AnthropicCacheControl type with TTL field;
AnthropicTool gains optional CacheControl pointer so the mimicry
path can attach a cache breakpoint to tools[-1] later.
- service/gateway_service.go: anthropicCacheControlPayload gains TTL;
marshalAnthropicSystemTextBlock and rewriteSystemForNonClaudeCode
emit ttl=5m by default.
The previous commit added FullClaudeCodeMimicryBetas() but the two
call sites in buildUpstreamRequest still hardcoded the old 3-token
subset. Anthropic now checks the complete set of beta tokens to
decide if a request qualifies as Claude Code. Wire them up:
- /v1/messages mimic path: requiredBetas = FullClaudeCodeMimicryBetas()
- /v1/messages/count_tokens mimic path: same + BetaTokenCounting
Haiku models keep the 2-token exemption (BetaOAuth + InterleaveThinking).
Before: the OpenAI-compat forwarders only called injectClaudeCodePrompt,
which prepends the Claude Code banner but leaves the rest of the body
in its original non-Claude-Code shape. The codebase already admits this
is insufficient (see the comment on rewriteSystemForNonClaudeCode in
gateway_service.go: "仅前置追加 Claude Code 提示词无法通过检测").
Effect: OAuth accounts served through /v1/chat/completions or /v1/responses
were detected as third-party apps and bled plan quota with:
Third-party apps now draw from your extra usage, not your plan limits.
Fix:
- apicompat.AnthropicRequest: add Metadata json.RawMessage so metadata
survives the OpenAI->Anthropic->Marshal round trip; without it the
downstream rewrite has no user_id to work with.
- service: extract applyClaudeCodeOAuthMimicryToBody, a ParsedRequest-free
variant of the /v1/messages mimicry pipeline
(rewriteSystemForNonClaudeCode + normalizeClaudeOAuthRequestBody +
metadata.user_id injection) so the OpenAI-compat forwarders can reuse it.
- service: add buildOAuthMetadataUserIDFromBody + hashBodyForSessionSeed
for the same reason (no ParsedRequest at the call site).
- ForwardAsChatCompletions / ForwardAsResponses: replace the 3-line
prompt-prepend with the full mimicry pipeline.
- applyClaudeCodeMimicHeaders: set x-client-request-id per-request
(real Claude CLI always does); missing/duplicated values are one more
third-party fingerprint signal.
No change to the native /v1/messages path: it already called the full
pipeline, we only lift those helpers into a reusable function.
Tests:
- go build ./... passes
- go test ./internal/service/... ./internal/pkg/apicompat/... passes
- lsp_diagnostics clean on all touched files
- pre-existing failures in internal/config are unrelated (env-sensitive
tests that also fail on upstream main)
Align Claude Code mimicry constants with the latest real CLI traffic
(see Parrot's src/transform/cc_mimicry.py). Anthropic now uses the full
set of anthropic-beta tokens to decide whether a request counts as
"official Claude Code"; requests missing tokens that real CLI ships
today are demoted to third-party usage:
Third-party apps now draw from your extra usage, not your plan limits.
Changes:
- claude/constants.go: add new beta tokens (prompt-caching-scope,
effort, redact-thinking, context-management, extended-cache-ttl) and
expose FullClaudeCodeMimicryBetas() for the OAuth mimicry path.
- claude/constants.go: bump default User-Agent to claude-cli/2.1.92.
- identity_service.go: bump defaultFingerprint User-Agent accordingly.
No behavioral change for clients that already send a newer UA (fingerprint
merge still prefers the incoming value).
keh4l