Introduction

DeepSeek Harness (DSH) uses a plugin architecture. ddll8023/dsh-codex is a DSH plugin that lets users connect directly to OpenAI Codex models via ChatGPT Plus/Pro OAuth. It does not require a DeepSeek API Key, addressing scenarios where Codex models are needed but configuring a DeepSeek Key is undesirable.

Core Features

  1. Codex model access: No DeepSeek API Key is required; it logs in via OAuth.
  2. Login methods: Supports browser OAuth login and Device Code browserless login.
  3. Models and input: The model selector automatically discovers Codex models and supports text streaming, tool calls, and image input.
  4. Fast mode: The chat input box can toggle between Standard and Fast on a per-session basis.
  5. Native web search: Supports Codex Native Web Search.
  6. Credentials and usage: Credentials are stored in DSH’s own credential service and refreshed automatically; usage display is via /codex status and /codex usage.

Installation and Enablement

Target: DSH Desktop 0.1.7-rc.2 package series.
Recommended installation with dsh plugin:

dsh plugin --profile web add github:ddll8023/dsh-codex

After installation, restart dsh web. Verify enablement:

dsh --profile web --dump-config | grep -A2 llm-codex

Once enabled, the OpenAI Codex Provider appears in the model selector.

Configuration

Edit via the Host plugin settings form, or place it in the config object of the llm-codex entry in the profile.

baseURL: https://chatgpt.com/backend-api
modelCatalogClientVersion: "0.157.0"
transport: sse
cacheRetention: short
nativeWebSearch: true
webSearchMode: live
refreshLeadTimeMs: 300000
streamIdleTimeoutMs: 300000
retryPolicy:
  mode: normal
  maxRetries: 2

CLI Usage

Login-related:
* /codex login: Browser OAuth login (Authorization Code + PKCE, callback http://localhost:1455/auth/callback).
* /codex login --device: Device Code flow for browserless environments (displays device code and verification URL).
* /codex logout: Deletes local OAuth credentials.
* /codex cancel: Cancels ongoing login.
Usage and status:
* /codex status: Login status, account ID, token validity, and current quota usage.
* /codex usage: Only queries and displays current account quota usage (5h/weekly/Spark sub-quota, including reset countdown).
Mode toggling:
* /codex speed standard: Switches the current session back to Standard.
* /codex speed fast: Switches the current session to Fast.

Security and Notes

  • Credential security: Credentials are stored in DSH’s own credential service (ctx.credentials, i.e. $DSH_HOME/.credentials.yaml), with file permissions 0600, hot reload, and serial writes. Tokens never enter logs, session events, telemetry, or error messages.
  • Key separation: DeepSeek API keys and Codex tokens do not interfere with each other.
  • Configuration conflicts: Do not add openai-codex to llm-pi-ai.providers; this activates another adapter in the host and conflicts with this plugin.
  • Compatible versions: Target: DSH Desktop 0.1.7-rc.2 package series.

Conclusion

This plugin connects to Codex via OAuth, provides native Fast mode and web search capabilities, and resolves credential management and usage monitoring concerns. For more details, see the GitHub repository.