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"Expecting property name enclosed in double quotes" Codex

Quick fix

Upgrade CC Switch to v3.16.4 or newer to fix the JSON parse error caused by a large request body not being decompressed.

Symptom

Section titled “Symptom”
Error output
CC Switch local proxy failed while handling Codex endpoint /responses. Provider: Agnes; model: agnes-2.0-flash; upstream_status: HTTP 400; cause: ***.BadRequestError: OpenAIException - {"error":{"message":"Expecting property name enclosed in double quotes: line 1 column 2 (char 1)","type":"BadRequestError","param":null,"code":400}}

Cause

Section titled “Cause”

Sending a large or complex request through Codex, the CC Switch Responses-to-Chat-Completions conversion layer hits a JSON serialization error, so the upstream provider rejects the request with HTTP 400.

The root cause is a large request body not being decompressed correctly before the JSON parse (with gzip, br, deflate, and zstd encodings stacked). The proxy handed the raw compressed bytes to serde_json, producing illegal JSON missing its double quotes ({property_name: "value"}, for instance). This was resolved in v3.16.4 by fixing the decompression logic.

Fix

Section titled “Fix”

  1. Upgrade CC Switch to v3.16.4 or newer, which fixes a large request body not being decompressed correctly before the JSON parse.

Affected Versions

Section titled “Affected Versions”
ToolCodex
Version<= 3.16.3 (在 v3.16.4 中修复)
PlatformsWindowsmacOS

Source Issues

Section titled “Source Issues”

This page is distilled from 2 real issues

FAQ

Section titled “FAQ”
After upgrading to v3.16.4 the JSON error is gone, but cache hit tokens stay at 0 while input tokens keep accumulating. Why?
That is a separate problem. A cache hit of 0 usually relates to the caching mechanism or API implementation of the upstream provider (Agnes AI), not the CC Switch JSON parsing fault.
Section titled “Related problems”
ANTHROPIC_BASE_URL rewritten to 127.0.0.1With local routing on, ANTHROPIC_BASE_URL pointing at http://127.0.0.1:15721 is expected. Move shared fields into 通用配置 and restart Claude Code.10 issues mergedYour access token could not be refreshedUpgrade cc-switch to v3.17.0+, which fixes the PROXY_MANAGED placeholder polluting OAuth credentials or causing a 401 during takeover.5 issues mergedtemporarily unavailable, so auto mode cannotUpgrade cc-switch to v3.15.0+ for the model mapping and thinking conversion fixes, or override the default model env var in general config.5 issues merged

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