built-in provider IDs: openai - Codex

Quick fix

Upgrade CC Switch to v3.16.4+, delete the old config and save again. Enable unified Codex session history and use openai_base_url.

Symptom

Error outputCopy

invalid configuration: model_providers contains reserved built-in provider IDs: `openai`.
Built-in providers cannot be overridden.
Rename your custom provider (for example, `openai-custom`).

Cause

CC Switch has a few legacy problems when modifying the Codex config file. First, older versions tried to write a `[model_providers.openai]` section straight into config.toml, but `openai` is a reserved built-in Codex provider ID that cannot be overridden, triggering the `invalid configuration` error. Second, they used `base_url` rather than `openai_base_url` when configuring the default endpoint, or left duplicate stale entries in the file, producing 401 unauthorized errors or requests still going to the official site.

Fix

1. 1

   Upgrade CC Switch to v3.16.4 or newer, which fixed the duplicate leftover `base_url` and added official session sharing.

2. 2

   Delete the old Codex config file, then save the provider config again in CC Switch so the new version generates the correct config structure.

   C:\Users\Administrator\.codex\config.toml

   # 错误写法（会导致 401）：
   # base_url = "http://127.0.0.1:15721/v1"
   
   # 正确写法（默认 OpenAI）：
   openai_base_url = "http://127.0.0.1:15721/v1"
   
   # 正确写法（自定义 provider）：
   # [model_providers.custom]
   # base_url = "http://127.0.0.1:15721/v1"

3. 3

   To share Codex session history between a third-party endpoint and your official account, enable 统一 Codex 会话历史 (unified Codex session history) under 设置 → Codex 应用增强 (Settings > Codex app enhancements) in CC Switch. Never override `[model_providers.openai]` in the config file by hand.

Affected Versions

ToolCodex

VersionCC Switch < 3.16.4 (修复于 v3.16.4)

PlatformsWindowsmacOS

Source Issues

This page is distilled from 3 real issues

• #1641codex应该使用openai_base_url而不是base_url 【C:\Users\Administrator\.codex\config.toml】 不然会401，codex cli发现的
• #3551Why does it automatically add “[model_providers.openai]” after I save, which prevents me from using it?
• #3889window配置了base_url,但一直把请求发到官网，是读不到配置文件还是没做兼容

FAQ

I deleted `[model_providers.openai]` from config.toml by hand — why does CC Switch add it back on save?

Automatic behaviour in older CC Switch when routing is on. Upgrade to v3.16.4+ and use 统一 Codex 会话历史 (unified Codex session history) under 设置 → Codex 应用增强 for sharing, rather than overriding the built-in openai provider by hand.

I configured `base_url` but requests still go to the official site, or I get a 401. What now?

There may be duplicate or stale `base_url` entries in the config file, or the field name may be wrong. Upgrade to v3.16.4+, delete the old config, and save again. Make sure the default config uses `openai_base_url`, and that a custom provider `base_url` sits inside its `[model_providers.<name>]` section.

Related problems

401 Unauthorized: Incorrect API key providedAfter switching to OpenAI Official or turning the proxy off, clear the leftover third-party OPENAI_API_KEY from ~/.codex/auth.json and restart Codex.2 issues mergedauth.json under .claude is forcibly replaced after a restart - CodexUpgrade cc-switch to the latest version, or turn proxy takeover off before signing in officially, so a stale snapshot cannot overwrite official credentials.5 issues mergedCC Switch local proxy failed while handlingUpgrade CC Switch to the latest version and start a new Codex conversation; invalid schema or image blocks left in old session history will keep triggering 400.43 issues merged