Bug: preserve Anthropic thinking replay through proxy-auth translation and clarify prompt-cache behavior #3719

Client or integration

Claude Code

Also reported with Claude Desktop 3P against a remote OpenCodex hub, using a connected client's proxy admission credential.

Area

Proxy and routing

Summary

Separate follow-up for the thinking/replay and prompt-cache request in #3646. This issue applies when Anthropic is the intended upstream. It does not cover Desktop date/hash alias discovery, hub registry ownership, client profile apply, or rejection of unresolved managed aliases; those belong to the remote-alias slice of #3646. Landing that slice does not establish that this replay/cache request is resolved.

The reporter asks that assistant thinking and redacted_thinking blocks survive subsequent turns to the intended Anthropic route, or that a supported untranslated path preserve the original Anthropic exchange. The guide should also explain how proxy authentication, native passthrough eligibility, and prompt-cache retention differ.

Evidence and limits:

• The current inbound translator explicitly drops assistant thinking and redacted_thinking blocks on replay (src/claude/inbound.ts, assistant-content conversion). The Claude Code guide documents this policy.
• Native passthrough requires an eligible unchanged Anthropic model and an actual Anthropic credential; a hub admission token by itself is not that credential. An exposed listener also requires the dedicated proxy admission header. Proxy-auth translation and native passthrough are different routes.
• Translation does not mean prompt caching is disabled. The Anthropic adapter still applies prompt-cache controls, including automatic caching for the native Anthropic endpoint. cacheRetention supports short (default, five minutes), long (one hour), and none.
• Bug: remote-hub Claude Desktop date aliases are forwarded to Anthropic as Opus (quota burn + cache miss) #3646 reports repeated cache misses and faster quota consumption after thinking responses. Neither a per-turn miss guarantee nor its causal attribution to dropped replay blocks has been reproduced in this follow-up. The report's claim that native Claude typically uses one-hour breakpoints also needs a controlled comparison. Do not infer billing or quota savings from the alias fix or from the configured retention duration alone.

Expected outcome:

• Define and implement supported Anthropic-to-Anthropic replay fidelity for proxy-auth traffic, preserving upstream-issued thinking signatures and opaque redacted-thinking blocks where the upstream/client contract requires them. Do not manufacture signatures or forward provider-specific blocks to unrelated providers.
• Verify a multi-turn thinking/tool-result exchange through the intended Anthropic route, including both block types, without replay validation errors or silently dropping required blocks.
• Compare cache creation/read usage across controlled continuation turns with stable model, credential scope, prompt prefix, tools, and retention settings. Distinguish replay changes from TTL expiry and other cache eligibility rules; record unexplained misses as unresolved.
• Document native passthrough eligibility separately from translated-route cache support and the existing retention choices. A global default change to one hour is not implied by this request.

Reproduction

Reported setup from #3646; this follow-up has not executed a new reproduction:

1. Connect Claude Code or Claude Desktop 3P to a remote OpenCodex hub using proxy authentication. Configure the hub's intended route to Anthropic with its existing managed credential.
2. Use a genuine, deliberately selected Anthropic model. Exclude unresolved Desktop aliases and other-provider routes from the comparison.
3. Continue a conversation after an assistant thinking response, including a tool-result continuation. Compare the types and ordering of replayed blocks across the translated boundary using synthetic or privately held content.
4. Record aggregate cache-read/cache-creation usage and elapsed time between turns. Compare supported short/long retention settings under otherwise stable conditions.
5. Separately exercise an upstream-provided redacted-thinking block in a controlled protocol fixture. No such redacted block or valid signed replay fixture was attached to Bug: remote-hub Claude Desktop date aliases are forwarded to Anthropic as Opus (quota burn + cache miss) #3646; current-version coverage remains to be collected.

The existing report's HTTP 404/429 table demonstrates the alias/routing symptoms. It is not a cache-replay reproduction or a measured cache-hit comparison.

Version

Original reporter: OpenCodex 2.42.0 Windows client and 2.41.0 WSL client; Claude Code 2.1.261. The exact remote hub build was not independently established in the issue body. A maintainer comment interpreted the version split differently, so record actual hub/client builds during reproduction rather than treating that interpretation as verified.

Current-version runtime reproduction: pending. This follow-up only confirms the translation policy and cache-control configuration by source inspection.

Operating system

Original report: Windows 11 and WSL, with a remote hub. Exact hub OS/build: not supplied.

Provider and model

Anthropic OAuth pool on the hub; original report names claude-opus-4-8 and claude-haiku-4-5. This follow-up concerns intentional Anthropic routing, independently of GPT/GLM Desktop alias failures.

Logs or error output

No isolated replay failure or controlled cache-usage trace is attached yet. The public report contains alias-related 404/429 observations; do not reuse those as proof of this separate remainder. No request content, credentials, thinking text, signatures, or opaque redacted payloads are included here.

Screenshots and supporting files

• Original request: Bug: remote-hub Claude Desktop date aliases are forwarded to Anthropic as Opus (quota burn + cache miss) #3646
• Maintainer recommendation to split thinking/cache follow-up: Bug: remote-hub Claude Desktop date aliases are forwarded to Anthropic as Opus (quota burn + cache miss) #3646 (comment)
• Existing public guide: https://opencodex.me/guides/claude-code/#native-claude-passthrough-subscription-pierce
• Repository guide: docs-site/src/content/docs/guides/claude-code.md, inbound translation table and native passthrough section.

Duplicate search found no separate issue covering this exact Anthropic proxy-auth replay/cache request:

• [Feature/UX]: add additive Claude Desktop catalog mode with honest native/OpenCodex switching #1213 remains open for honest Desktop native/gateway coexistence and switching. It does not own thinking replay or cache fidelity.
• [Bug]: Intermittent consecutive zero cache hits for Hermes requests through OpenCodeX #3433 remains open for Hermes Chat Completions to native OpenAI/Codex cache affinity. It is a different protocol/provider path.
• Claude Desktop 3P Auto Mode classifier retries after 64-token Anthropic OAuth outputs #545 is closed after stack 4/7: keep an explicit thinking disable through translation (#545) #954 preserved explicit thinking: disabled for the Desktop classifier. That is not assistant thinking-block replay; its correlated classifier sample actually recorded cache hits.
• The request couldn’t be completed. #994 is a closed OpenCode reasoning-content continuation report, with missing provider/model detail at closure. A comment mentions the same inbound drop policy, but it does not cover the specific Anthropic prompt-cache request here.
• [architecture][memory] Make 32 concurrent tool-recall sessions protocol-safe and memory-bounded #820 is a closed concurrency/memory architecture issue with broad protocol-preservation requirements, not an active owner for this remainder.

Search scope: all issue states; title/body/comments for redacted_thinking, thinking cache, thinking replay, cacheRetention, and passthrough proxy; additional Anthropic/cache and open cache searches. Related issue bodies and relevant later comments were inspected, not just titles.

Redacted configuration

Reported configuration shape, not an executable configuration file:

hub runtimeRole: hub
connected client runtimeRole: client
Claude integration authMode: proxy
client credential: proxy admission token only (value omitted)
intended upstream: Anthropic, using a configured hub credential
cacheRetention: short (default); compare long separately

Checks

• I searched existing issues and documentation.
• I removed secrets, tokens, account details, request credentials, and personal data.