[vadymhimself]

Summary

• Anthropic refuses an OAuth turn that bills against an empty extra-usage balance with HTTP 400 invalid_request_error. The message is either "You're out of extra usage. Add more at claude.ai/settings/usage and keep going." or the newer "Third-party apps now draw from your extra usage, not your plan limits. Add more at claude.ai/settings/usage and keep going." Public reports: [BUG] CLI completely blocked by "out of extra usage" error despite Max 20x plan at only 10% usage anthropics/claude-code#45020, Anthropic OAuth (Claude Pro/Max subscription) hits "You're out of extra usage" on every real request — routes through pay-per-token endpoint instead of subscription quota NousResearch/hermes-agent#65564 and #79760, and fix: Claude OAuth proxied requests rejected as third-party extra usage (all harnesses) decolua/9router#4353.
• Today comboFailureDecision classifies that 400 as a terminal invalid request. As a result, a combo such as Claude OAuth → GPT ends the turn instead of moving to its next tier.
• This change adds isAnthropicExtraUsageFailure in src/providers/anthropic-billing-refusal.ts. It uses the same evidence bar as the existing credit-balance refusal: an invalid_request_error envelope with the exact wording, or the exact prose together with that structured code. The check runs before the generic invalid-request stop and grants a target-scoped hop.
• The cooldown stays target-scoped on purpose. Unlike an empty prepaid key balance, the third-party wording can depend on the request shape, so this does not cool the whole provider.
• Quoted ("Diagnostic: …"), coded (context_length_exceeded), other-typed (api_error) and uncoded bare-prose variants all stay terminal.
• The behavior is carried over from the vadymhimself fork (e987656, 79faf06), which has run it on a hosted gateway since 2026-11-08. The fork's version matched any substring in classifyError. Here it is reworked to follow upstream's exact-envelope pattern (fix(router,combos): hop and cool provider on upstream account quota exhaustion #7625).

Verification

All commands used the pinned Bun 1.4.4 with an isolated HOME.

• bun test tests/routing/router-anthropic-billing-failover.test.ts: 3 pass, 0 fail. With the src/ change reverted, the new test fails (2 pass, 1 fail).
• bun scripts/test.ts --changed=upstream/dev: 43601 pass, 6 fail. All six fail identically without this change:
  • codex-composed-acceptance ×2 (fails the same way on the base)
  • connected-client runtime probe scope
  • link-ocx-child-e2e ×2
  • retained sync and serve-options
• bun run typecheck, bun run structure:check and bun run privacy:scan all pass.
• I updated structure/runtime.md to match.

Checklist

• Scope stays focused and avoids unrelated cleanup.
• Docs or release notes were updated when needed.
• Security-sensitive changes were reviewed for secrets, auth, and unsafe defaults.

Review readiness checklist

This PR stays in draft until every box below is ticked. Tick all four boxes once the requirements are met:

• Required local validation passed; commands, results, and any full-suite exception are documented.

• I pushed my PR to a recent dev commit (at most 10 behind; a maintainer may still ask for the exact tip before merge).

• I resolved all correct Codex and CodeRabbit findings.

• My PR is ready for review.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Combo routing now moves to the next option for recognized Anthropic extra-usage refusals in supported plain-text and structured error responses. The cooldown applies only to the affected target. Other error types, quoted messages, and unsupported coded variants remain terminal.
• Documentation
  • Runtime guidance now describes the supported refusal messages, the error details required for failover, target-specific cooldown behavior, and cases that remain terminal.

[github-actions]

✅ Deterministic PR hygiene checks passed.

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• review readiness checklist open (0/4 boxes ticked).

What to do

• Tick all four boxes in the PR description once you're done (currently 0/4).

Review readiness checklist

• ⬜ Required local validation passed; commands, results, and any full-suite exception are documented.
• ⬜ I pushed my PR to a recent dev commit (at most 10 behind; a maintainer may still ask for the exact tip before merge).
• ⬜ I resolved all correct Codex and CodeRabbit findings.
• ⬜ My PR is ready for review.

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This PR stays in draft until every box above is ticked.

Hygiene

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[coderabbitai]

No actionable comments were generated in the recent review.

Walkthrough

The change adds recognition for specific Anthropic extra-usage refusals and uses matching HTTP 400 responses to trigger combo failover. Tests cover accepted and terminal response variants. Runtime documentation describes the refusal patterns and handling.

Changes: Anthropic extra-usage failover

Layer / File(s)	Summary
Refusal classification src/providers/anthropic-billing-refusal.ts	The classifier recognizes exact extra-usage refusal messages and checks the HTTP status, code, and response format. A shared helper normalizes provider-prefixed messages.
Combo failover and validation src/combos/failover.ts, tests/routing/router-anthropic-billing-failover.test.ts, structure/runtime.md	Combo failure handling hops when the classifier matches. Tests cover accepted and terminal variants. Runtime documentation describes the refusal patterns and handling.

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Possibly related issues

• lidge-jun/opencodex#7965 — The change treats a matching Anthropic extra-usage refusal as a target-scoped hop, but does not add the requested combo_exhausted diagnostic.
• lidge-jun/opencodex#8288 — The change recognizes the reported Anthropic OAuth refusal wording, but does not address the issue’s instruction-placement cause.

Merge Risk: Minimal · up to e1549

This change lets a combo move to its next tier when Anthropic refuses a request because the extra-usage balance is empty. Quoted, coded or other-typed variants still stop the combo as before. No concrete risk was found that should block merging.

Pre-merge checks: 4

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title "fix(combos): hop past Anthropic's extra-usage refusal" names the main change. The changeset adds isAnthropicExtraUsageFailure, wires it into decideComboFailure in src/combos/failover.ts so …
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Title check

Explanation

The title "fix(combos): hop past Anthropic's extra-usage refusal" names the main change. The changeset adds isAnthropicExtraUsageFailure, wires it into decideComboFailure in src/combos/failover.ts so a matching status returns "hop", and adds tests and docs for the Anthropic extra-usage refusal. The title is short, single-sentence, and specific, so it passes.

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Recent review info

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• Source mode: Auto
• Repository: lidge-jun/opencodex
• Branch: dev
• File: .coderabbit.yaml
• Commit: e85a975
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• src/combos/failover.ts

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