DeepSeek Harness — OpenAI Codex Plugin

Use your ChatGPT Plus/Pro subscription as an LLM provider in the DeepSeek Harness.

This plugin adds device-code OAuth login through both the Web settings UI and /codex CLI command — no browser callback server or localhost listener. After login, Codex models appear alongside your other providers in the DSH model selector, the access token refreshes automatically without a restart, and a Codex limits popup above Settings shows the 5-hour and weekly balance.

How it works

1. In the Web app, open Settings → OpenAI Codex → Sign in. The page opens OpenAI, shows the one-time code, and updates automatically after approval. Headless/TUI users can run /codex login for the same device-code flow.
2. The plugin stores the token triple {access, refresh, expires} in $DSH_HOME/openai-codex.json and publishes only the live access token to the DSH credential seam under OPENAI_CODEX_TOKEN.
3. Your settings.yaml maps that credential to the openai-codex route, and dsh-llm-pi-ai uses the built-in openai-codex-responses API to serve all Codex models.
4. The plugin refreshes the token automatically ~5 minutes before expiry.
5. In Web, Codex limits calls OpenAI from the server and returns only normalized usage percentages, reset times, and optional credit balances; OAuth tokens never cross into the browser.

The limits view uses OpenAI's undocumented Codex usage endpoint, so its response shape may change without notice.

Install

# Add the plugin to your profile (web, tui, headless, …)
dsh plugin --profile web add @syncended/dsh-codex

# Restart dsh

Note: the profile is a pnpm workspace root, so on some dsh versions the add command needs -w: dsh plugin --profile web add -w @syncended/dsh-codex.

The plugin registers the openai-codex route defaults automatically, so no dsh settings set is needed. In Web, use Settings → OpenAI Codex. The /codex login | status | logout commands remain available in every profile.

Like DSH's other credential settings, Web login is restricted to a loopback Web session. For a remote deployment, run /codex login on the host-facing profile instead.

Commands

Command	Description
/codex login	Start device-code OAuth login
/codex status	Show token status and expiry
/codex logout	Clear the stored token

Configuration

The plugin accepts these optional config values (rarely needed):

Key	Default	Description
clientId	app_EMoamEEZ…hrann	OpenAI OAuth client id
credentialRef	OPENAI_CODEX_TOKEN	Credential seam ref
deviceCodeTimeoutSeconds	900 (15 min)	How long the user has to approve
refreshWindowMs	300_000 (5 min)	Refresh this far before expiry
tokenFile	$DSH_HOME/openai-codex.json	Override token persistence path

Requirements

• ChatGPT Plus or Pro subscription
• DeepSeek Harness ≥ 0.1.0-rc.6
• Node.js ≥ 18

License

MIT — see LICENSE.