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exceeded the 64000/128000 output token maximum - Claude Code

Quick fix

Remove or rewrite the rejected MCP tool JSON Schema pattern to prevent Codex OAuth from falsely reporting an output token limit.

Symptom

Section titled “Symptom”
Error output
API Error: Claude's response exceeded the 64000/128000 output token maximum

Cause

Section titled “Cause”

The Codex OAuth backend may reject an MCP tool containing a specific JSON Schema `pattern` before processing the request, then return HTTP 200 with zero input/output tokens, an empty `output`, and `response.incomplete`. This is not actual output truncation.

cc-switch’s Responses→Anthropic converter maps this termination event to `max_tokens`, so Claude Code displays it as an output token limit. Actual output truncation should have non-zero usage; the verified version in this issue was cc-switch v3.20.4.

Fix

Section titled “Fix”

  1. Check the MCP tool JSON Schema included in the request. Temporarily remove the tool containing a `pattern` regex with nested repeated groups, then retry.

  2. If the tool must remain, replace the verified problematic `^[^/\s]+(?:\/[^/\s]+)+$` with the equivalent flat character class `^[A-Za-z0-9_\-.\/]+$`, then retry the request.

Affected Versions

Section titled “Affected Versions”
ToolClaude Code
Version3.20.4（已验证受影响）
PlatformsUnknown

Source Issues

Section titled “Source Issues”

This page is distilled from 1 real issues

FAQ

Section titled “FAQ”

(No FAQ yet)

Section titled “Related problems”
Invalid schema for function — CodexUpgrade CC Switch to a version including the v3.18.0 fix for `parameters.type:null`; track the original issues for other `null` schema variants.13 issues merged[DISCUSS] Support for pi coding agentThis is a feature request merged into tracking issue #1855; the original post provides no verifiable solution.1 issues mergedReasoning effort dropped, Claude CodeWait for the next release containing the merged Responses proxy fix so reasoning.effort can be forwarded after model mapping.2 issues merged

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