Claude Code builds Anthropic-Beta per request instead of sending a fixed list.
Captured from an isolated 2.1.220 profile pointed at api.anthropic.com through
a local proxy, over two rounds covering 11 model IDs and the [1m] variants:
constant claude-code, interleaved-thinking, redact-thinking,
thinking-token-count, context-management, prompt-caching-scope
tools advanced-tool-use-2025-11-20 only when tools are declared
model mid-conversation-system-2026-04-07 only on models that accept a
role=system turn
[1m] context-1m-2025-08-07, directly after claude-code-20250219 rather
than at the end
trailing effort-2025-11-24, then server-side-fallback-2026-06-01
claude-sonnet-5 emits mid-conversation-system-2026-04-07, so it accepts a
role=system turn and must not sit in the legacy reminder whitelist.
count_tokens does not reuse the inference fingerprint. Running /context in an
interactive session issues 37 identical calls, which made the endpoint
observable for the first time: four betas only, and 21 headers rather than 22
because X-Stainless-Timeout is absent. The profile is selected from the request
path so no call site has to thread another flag.
Detect confirmed CLI, sdk-cli and VSCode callers before mutation so native
software, system, tool, cache and beta shapes pass through, while unconfirmed
OAuth clients receive a coherent minimum CLI identity.
Persist each Claude OAuth credential's upstream account metadata and one stable
device ID, derive one stable session per agent conversation, and keep body and
header identity synchronized across Messages, streaming and count_tokens.
Alias every cloaked third-party custom tool through caller-stable opaque MCP
names and restore declarations, choices, history, references, non-stream
responses and SSE events without changing tool ownership.
Implement the Claude Code 2.1.220 CCH algorithm over the final serialized
request bytes, align currentDate and first-user cache layout, update the
official beta/header baseline, and use upstream count_tokens for OAuth and
first-party Anthropic credentials.
Match the 2.1.220 TLS ClientHello so the transport fingerprint agrees with the
identity the request now claims, and document the CLI defaults and automatic
OAuth signing / tool alias behaviour in config.example.yaml.
- Removed deprecated interceptor and executor-related methods, including `callRequestInterceptor`, `callResponseInterceptor`, and `callStreamChunkInterceptor`.
- Consolidated unused logic and pruned redundant imports to streamline `adapters.go`.
- No functional changes.
- Updated `ensureCacheControl` to inject cache_control into the last non-deferred tool instead of the last tool.
- Adjusted `injectToolsCacheControl` to ignore tools marked with `defer_loading` for prompt caching.
- Added unit tests to validate behavior for deferred tools, existing cache_control, and mixed tool arrays.
Closes: #4561
- Updated Kimi and Gemini executors to use `TranslateRequestWithCodexMultiAgentV2` for improved multi-agent v2 optimization.
- Enhanced configuration and API server to support `CodexOptimizeMultiAgentV2`.
- Added codex multi-agent V2 optimizations in `config`, `executor`, and `watcher` modules.
- Introduced `SetStringIfDifferent`, `SetBoolIfDifferent`, and similar helpers in `payload_helpers` to avoid unnecessary writes during JSON modifications.
- Simplified message patching in `kimi_executor` for reasoning and tool call adjustments.
- Updated all executors (Gemini, Codex, XAI, Antigravity, etc.) to use the new helpers, enhancing readability and potentially reducing overhead.
- Removed obsolete `filterKimiEmptyAssistantMessages` function in `kimi_executor`.
- Added an `incomingHeaders` argument to `applyClaudeHeaders` to enable external header injection for flexibility.
- Updated Kimi executor to delegate header support to Claude executor, facilitating upstream request logging and beta header forwarding.
- Introduced tests for delegated configuration, header handling, and upstream request/response logging to improve coverage.
- Updated `normalizeClaudeSamplingForUpstream` to delete `top_p` from payloads.
- Adjusted test to validate the removal of both `temperature` and `top_p`.
Closes: #4383
- Introduced `AttachCacheControl` and `AttachMessageCacheControl` utilities for consistent cache control injection in content parts and messages.
- Updated Claude translator modules to preserve and apply cache control metadata for responses, messages, tools, and parts.
- Added unit tests to validate proper cache control behavior across multiple scenarios.
Closes: #4146
- Verified proper chunking and streaming of SSE events in `ExecuteStream`.
- Refactored executor to ensure complete SSE event delivery without partial fragments.
Closes: #4121
- Introduced `RebuildMidSystemMessage` field in config to move system messages into the top-level Claude system field.
- Updated executor to handle mid-system message rebuilding when enabled via config or auth attributes.
- Added unit tests to verify rebuilding behavior and default behavior when disabled.
- Updated configuration example and API handlers to support the new field.
Closes: #3792
- Introduced `disable-claude-cloak-mode` configuration to globally disable Claude cloak mode with credential-level overrides.
- Enhanced `getCloakConfigFromAuth` to support fallback to metadata for cloak settings.
- Updated cloak configuration precedence logic, integrating global, credential, and default modes.
- Updated config and watcher diff handling to include `disable-claude-cloak-mode`.
Closes: #2789
- Added `sanitizeClaudeWebSearchDomains` to remove empty `allowed_domains` and `blocked_domains` fields for built-in web_search tools, addressing ambiguity errors from Anthropic.
- Integrated domain sanitization into the Claude message preparation pipeline.
- Added test cases to validate correct handling of empty and non-empty domain fields across various tool types.
Closes: #2681
- Updated Antigravity Credits fallback to handle KV store unavailability as a service error.
- Enhanced signature caching mechanisms with request-time KV access and sliding expiration.
- Added and improved tests for KV client interactions, including error handling and expiration behaviors.
- Introduced `CacheSignatureBestEffort` for non-critical signature caching and clarified function flows with required context.
- Ensured consistent error reporting for missing or unavailable KV stores in various scenarios.
- Replaced direct `homekv` calls with injectable KV client interfaces for `antigravity` and `codex_reasoning_replay` modules.
- Improved error reporting and handling for KV operations, including `KVGet`, `KVSet`, `KVDel`, and `KVExpire`.
- Introduced dedicated fake KV clients for expanded and granular test coverage.
- Added new unit tests to validate KV client behaviors and error scenarios, ensuring robustness and sliding expiration functionality.
- Added an example plugin `host-model-callback` in Go to summarize host model callbacks.
- Implemented `cliproxy_plugin_init`, `cliproxyPluginCall`, and other plugin functions for callback handling.
- Introduced API handlers for `ModelExecution` and `ModelExecutionStream` with support for both streaming and non-streaming requests.
- Included unit tests (`model_execution_test.go`) to validate execution logic and streaming responses.
- Updated `NewUtlsHTTPClient` to support context-aware RoundTrippers for protected hosts (e.g., Cloudflare bypass).
- Replaced `anthropicHosts` with `utlsProtectedHosts` to generalize host handling logic.
- Added unit test to validate context-based RoundTripper behavior.
- Replaced `NewProxyAwareHTTPClient` with `NewUtlsHTTPClient` in relevant executors for improved TLS fingerprinting.
Closes: #3680
- Replaced `NewUsageReporter` with `NewExecutorUsageReporter` to include executor type in usage records.
- Updated all executors to use the new reporter implementation.
- Extended `UsageReporter` to track and publish executor type.
- Added tests to validate proper executor type recording and handling.
- Enhanced RedisQueue plugin and payload schema with executor type support.
- Introduced Time-To-First-Token (TTFT) measurement and reporting across major executors.
- Added TTFT calculation to `UsageReporter`, including support for HTTP clients and WebSocket communication.
- Updated tests to validate TTFT tracking in streamed and non-streamed scenarios.
- Ensured integration with `usage` plugin and augmented usage records with TTFT data.
- Introduced `SetTranslatedReasoningEffort` method in `UsageReporter` to capture and log reasoning efforts from translated payloads.
- Updated executors to incorporate the new reporting functionality for handling reasoning efforts across various providers.
- Enhanced logging for thinking level extraction with new helper function `ExtractTranslatedReasoningEffort`.
- Introduced `resolvePayloadRulePaths` function to dynamically resolve rule paths supporting array queries and complex logic.
- Updated payload processing logic (`apply defaults`, `overrides`, `filters`) to handle resolved paths for better flexibility.
- Added helper functions for path parsing, query matching, and logical resolution to improve modularity and reusability.
- Introduced payload condition match logic, including `match`, `not-match`, `exist`, and `not-exist` rules in `PayloadConfig`.
- Enhanced `payloadModelRulesMatch` function to support conditional checks at various levels.
- Added helper methods for evaluating JSON path conditions and values.
- Updated tests to validate new conditional rules against different payload scenarios.
- Added `count` attribute to `homeAuthCount` requests to improve home message batching.
- Enabled usage statistics for home mode by default and added config-level enforcement.
- Adjusted failure logging to include detailed metadata in `UsageReporter`.
- Updated multiple executors to pass error details to `PublishFailure` for better debugging.
- Enhanced unit tests to validate `count` behavior and usage statistics enforcement across components.
- Updated all references from v6 to v7 for `github.com/router-for-me/CLIProxyAPI`.
- Ensured consistency in imports within core libraries, tests, and integration tests.
- Added missing tests for new features in Redis Protocol integration.
- Implemented `validateClaudeStreamingResponse` to ensure upstream streaming data integrity.
- Added new tests to verify response validation, including empty streams, error events, incomplete streams, and valid streams.
- Integrated validation logic into the Claude executor's streaming handler, returning detailed errors for malformed upstream data.
Fixed: #2193
All streaming executors use bare channel sends (out <- chunk) inside goroutines
that process upstream SSE responses. When the downstream consumer disconnects
(client timeout, network drop, etc.), these sends block indefinitely, causing
the goroutine and all associated resources (HTTP response body, scanner buffers,
translation state) to leak permanently.
Over time, leaked goroutines accumulate monotonically, leading to RSS growth
from ~30MB to 3.7GB+ and eventual OOM kills on resource-constrained VPS hosts.
Fix: Replace all bare 'out <- ...' sends with:
select {
case out <- ...:
case <-ctx.Done():
return
}
This ensures goroutines terminate promptly when the request context is canceled,
allowing GC to reclaim all associated resources.
Affected executors (9 files, 36+ send sites):
- antigravity_executor.go (5 sites)
- gemini_cli_executor.go (6 sites)
- gemini_vertex_executor.go (6 sites)
- aistudio_executor.go (4 sites)
- gemini_executor.go (3 sites)
- openai_compat_executor.go (3 sites)
- claude_executor.go (4 sites)
- codex_executor.go (2 sites)
- kimi_executor.go (3 sites)
- Introduced `DisableImageGenerationMode` with support for `false`, `true`, and `chat` values.
- Updated payload handling to preserve `image_generation` on images endpoints when `chat` mode is enabled.
- Modified OpenAI image handlers (`ImagesGenerations`, `ImagesEdits`) to respect tri-state logic.
- Added unit tests for `DisableImageGenerationMode` behavior and endpoint-specific handling.
- Enhanced configuration diff logging to support `DisableImageGenerationMode`.
Address Gemini code review suggestion: the reverseMap can contain at
most len(oauthToolRenameMap) entries, so pre-allocating avoids
reallocations as entries are added.
remapOAuthToolNames renames lowercase client-sent tools (e.g. `glob` →
`Glob`) to Claude Code equivalents on OAuth requests to avoid tool-name
fingerprinting. The reverse pass previously ran against a *global*
reverse map and rewrote every tool_use block whose name matched any
value in oauthToolRenameMap — regardless of what the client actually
sent.
For clients that send mixed casing (notably Amp CLI — `Bash`, `Read`,
`Grep`, `Task` alongside `glob`, `skill`, etc.) this corrupted the
response. Any forward rename in the request set the "renamed" flag,
which then unconditionally lowercased every `Bash` in the response to
`bash`. Amp's tool registry has `Bash`, not `bash`, so it rejected the
tool_use with `tool "bash" is not allowed for smart mode` and tool
execution failed.
Fix: `remapOAuthToolNames` now returns a per-request map keyed on the
upstream (TitleCase) name valued with the original client-sent name.
The reverse functions take this map and only touch entries in it.
Names the client sent in TitleCase pass through untouched in both
directions.
- Change remapOAuthToolNames signature from `([]byte, bool)` to
`([]byte, map[string]string)`; populate at every rename site
(tools[], tool_choice.name, message tool_use, tool_reference,
nested tool_reference inside tool_result).
- Change reverseRemapOAuthToolNames and
reverseRemapOAuthToolNamesFromStreamLine to accept and consume the
per-request map; remove the global oauthToolRenameReverseMap.
- Update all three executor call sites (Execute, ExecuteStream direct
passthrough, ExecuteStream translated) + count_tokens.
- Add regression tests for the mixed-case scenario in both the
non-streaming and SSE code paths.
Anthropic has moved the 1M-context-window feature to General Availability,
so the context-1m-2025-08-07 beta flag is no longer accepted and now causes
400 Bad Request errors when forwarded upstream.
Remove the X-CPA-CLAUDE-1M detection and the corresponding injection of the
now-invalid beta header. Also drop the unused net/textproto import that was
only needed for the header-key lookup.
- Introduced `WithProxyURL` variants for `CodexAuth`, `ClaudeAuth`, `IFlowAuth`, and `DeviceFlowClient`.
- Updated executors to use proxy-aware constructors for improved configurability.
- Added unit tests to validate proxy override precedence and functionality.
Closes: #2823
- Use buildTextBlock for billing header to avoid raw JSON string interpolation
- Fix empty array edge case in prependToFirstUserMessage
- Allow remapOAuthToolNames to process messages even without tools array
- Move claude_system_prompt.go to helps/ per repo convention
- Export prompt constants (ClaudeCode* prefix) for cross-package access
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
A/B testing confirmed that Anthropic uses tool name fingerprinting to detect
third-party clients on OAuth traffic. OpenCode-style lowercase names like
'bash', 'read', 'todowrite' trigger extra-usage billing, while Claude Code
TitleCase names like 'Bash', 'Read', 'TodoWrite' pass through normally.
Changes:
- Add oauthToolRenameMap: maps lowercase tool names to Claude Code equivalents
- Add oauthToolsToRemove: removes 'question' and 'skill' (no Claude Code counterpart)
- remapOAuthToolNames: renames tools, removes blacklisted ones, updates tool_choice and messages
- reverseRemapOAuthToolNames/reverseRemapOAuthToolNamesFromStreamLine: reverse map for responses
- Apply in Execute(), ExecuteStream(), and CountTokens() for OAuth token requests
Only for Claude OAuth requests, sanitize forwarded system-prompt context before
it is prepended into the first user message. This preserves neutral task/tool
instructions while removing OpenCode branding, docs links, environment banners,
and product-specific workflow sections that still triggered Anthropic extra-usage
classification after top-level system[] cloaking.
