Codex Conversations for DeepSeek Harness

August 31, 2026 · View on GitHub

Unreleased adaptation: this branch targets DSH 0.1.2-alpha.2. npm versions and tags are unchanged; installation examples for published releases do not establish compatibility with the new DSH. See compatibility notes.

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npm package: relay-dsh-plugin-codex · All Relay DSH plugins

Run Codex inside official DeepSeek Harness without switching interfaces or maintaining a DSH fork.

relay-dsh-plugin-codex adds Codex as a native conversation backend to the official DeepSeek Harness (DSH) Web UI. You keep DSH's workspace, conversation history, composer, approvals, and tools while each DSH Session continues one Codex App Server Thread. The plugin installs independently; no Relay checkout is required.

Try It on Official DSH

Authenticate with an official Codex client before the first Session. Codex CLI users can run:

codex login

The install requires Node.js 22.13 or newer and pnpm on PATH. Stop DSH Web, install the stable plugin, and restart DSH:

npx @deepseek-ai/dsh@0.1.1-rc.2 plugin --profile web add relay-dsh-plugin-codex@latest
npx @deepseek-ai/dsh@0.1.1-rc.2 web

Open New Session, select a workspace, choose Codex from the mode menu, and send a message.

Codex and Claude Code in the DSH New Session mode menu

The screenshot was captured from official DSH 0.1.1-rc.2 with the Codex and Claude plugins installed. If you install only this plugin, only Codex is added.

Watch Plugin Manager find and install this package in 40 seconds · review all Relay DSH plugins

If this removes an interface switch from your DSH workflow, star this plugin and share your DSH version or install feedback. That signal helps other DSH users find a tested Codex backend.

Do I Need This Plugin?

Install it when you want to:

use Codex inside DSH instead of switching to a separate Codex interface;
keep DSH's native conversation history, composer, approvals, and questions;
let one DSH Session continue the same Codex App Server Thread across turns;
use Codex models, reasoning effort, images, interruption, and DSH-contributed tools in the same conversation.

You do not need it to use DSH's standard agents. It also does not add Relay Events, file browsing, or a terminal panel. Those are separate optional plugins.

Complete Setup and Compatibility

The steps below were validated with:

DeepSeek Harness 0.1.1-rc.2, commit b150a551
Node.js 22.13 or newer
pnpm available on PATH

DSH is currently a developer preview and may introduce compatibility-breaking changes. This repository tracks official releases and records its tested version here.

1. Prepare Codex authentication

The plugin installs a pinned official @openai/codex runtime and launches it in App Server mode. The runtime contains native binaries for macOS, Windows, and Linux on x64 and arm64, so DSH does not need to find a codex command on its PATH.

Codex authentication is still required. Install or open an official Codex client and authenticate it before starting your first DSH Codex session. When using the CLI, verify the shared local credentials with:

codex --version
codex login

See the official Codex CLI guide and authentication documentation for installation and sign-in options. Credentials stay under Codex's normal local authentication mechanism; this plugin does not collect them. Installing this plugin supplies its App Server runtime, but does not add a global codex shell command.

2. Choose a package source and install

Stop a running DSH Web process before changing Profile bundles. Choose one of the following sources.

Stable npm release

The published npm package name is relay-dsh-plugin-codex. Use @latest to install the current stable release:

npx @deepseek-ai/dsh@0.1.1-rc.2 plugin --profile web add relay-dsh-plugin-codex@latest

At the time of writing, latest resolves to stable version 0.1.5. The linked npm page is the source of truth for the current version.

npm prerelease (recommended during DSH preview)

Use @next to try the newest release candidate that has passed the repository's CI publishing and official DSH compatibility checks. The current candidate also contains the bundled cross-platform App Server runtime, so DSH does not depend on a global codex executable:

npx @deepseek-ai/dsh@0.1.1-rc.2 plugin --profile web add relay-dsh-plugin-codex@next

This branch prepares 0.1.6-rc.1 for next, without changing latest. Check the npm registry for the currently published dist-tag before installing.

This prerelease preserves native service-tier and resumed-thread settings, stops late commands belonging to canceled turns, rejects stale interaction replies, and retains dynamic-tool errors. New conversations receive bounded execution guidance; set codexExecutionGuidance: false to disable it, or codexExecutionMode: native to compare without DSH dynamic tools and guidance. The default mode is enhanced. The host identifies itself as DSH and does not advertise unimplemented Desktop attestation or MCP App HTML rendering. Dependency discovery reports existing paths.

The bundled runtime remains @openai/codex@0.149.0; Desktop's experimental binary is not redistributed or required. This is not complete Desktop parity. Known limitations include occasional empty native command-event output even when the model received the error, and a macOS locale issue affecting tools such as shasum. These have not been declared fixed. To roll back, stop DSH, reinstall relay-dsh-plugin-codex@0.1.5, restore any changed profile configuration, and restart.

GitHub development build

Install the current main branch when testing an unreleased change:

npx @deepseek-ai/dsh@0.1.1-rc.2 plugin --profile web add github:yangbobo2021/relay-dsh-plugin-codex#main

main can change at any time. For a reproducible GitHub install, pin a Tag or full Commit SHA instead. For example:

npx @deepseek-ai/dsh@0.1.1-rc.2 plugin --profile web add github:yangbobo2021/relay-dsh-plugin-codex#v0.1.6-rc.1

The official DSH CLI initializes the web Profile if it does not exist, asks pnpm to install the selected package, and adds the plugin's bundle layer. No Relay checkout is required. If you already installed the dsh command, replace the npx @deepseek-ai/dsh@0.1.1-rc.2 prefix with dsh in any command above.

3. Start or restart DSH Web

npx @deepseek-ai/dsh@0.1.1-rc.2 web

If you use an installed command, run dsh web instead. Bundle membership is read at startup, so restarting after installation, update, or removal is required.

4. Start a Codex conversation

Open the DSH URL printed in the terminal. The default is http://127.0.0.1:3080.
On first launch, read the DSH testing notice and select Continue.
Select Add workspace in the left sidebar and choose the project directory Codex may work in.
Select New Session.
Open the mode menu labeled Standard mode and choose Codex.
Enter a message and send it. Choose the backend before the first message; existing sessions keep the backend with which they were created.

There is no separate activation command. A successful install plus a DSH restart activates the bundle and registers the managed Codex mode automatically.

5. Import existing Codex sessions for a Workspace

Select the compact Codex import icon below the Workspace list and above Settings.
In the dialog, confirm or change the visible Target Workspace, then select Scan sessions. The current Session owner or recent Workspace is only the initial selection; scanning never starts before this confirmation.
Review each eligible Codex Thread's full ID, title, source path, last activity, and ready or recoverable status. Select one, several, or all Threads.
Select Import selected.
Confirm that imported rows already show their Codex titles and source activity order, then open any Session and continue chatting.

Only eligible Threads from the explicitly selected Workspace are shown. Already-bound Threads and Threads from another Workspace cannot be selected. Titles and recency are available before a Session is opened; batch execution time does not replace the Codex inventory thread/list.updatedAt order. Codex App Server remains authoritative for model context, tool state, and compaction. DSH stores native user/assistant presentation history and the durable one-to-one binding; it does not copy private Codex runtime records. Each time an imported Session is opened, the plugin reads that Codex Thread once and appends any missing terminal user/assistant Turns to DSH's presentation history, including interrupted or failed Turns with visible messages. Only an inProgress Turn waits for the next open. It does not poll in the background, synchronize while the Session stays open, or add a manual refresh action.

What Works

One persistent Codex App Server Thread per DSH Session
Model and reasoning-effort selection
Streaming answers and reasoning in the native DSH conversation
Live output from long-running Codex shell commands in newly created Sessions, retained in DSH history
DSH approval and user-question flows
Images, interruption, and continuation
Generic DSH tools exposed under the Codex App Server dsh namespace
Optional terminal transport when the separate Relay terminal plugin is present

Tools execute through the owning Agent's DSH tool runtime and remain subject to DSH permissions and Codex approval behavior.

Reliability and App Server Lifecycle

The DSH Host plugin owns the Codex App Server process. It starts one child while the plugin activates, before Codex model discovery, and stops it when DSH or the plugin shuts down. The default child comes from the pinned @openai/codex dependency, so a global codex command is not required.

Open Settings → Advanced to see whether Codex is Connected, Not started, Starting, Connection failed, or Codex unavailable. A forked Session that inherited Codex history without a safe one-to-one binding shows Rebind required in its Session header. Installation and connection errors include a stable error code and a next action; raw errors such as spawn codex ENOENT are not shown as the user instruction.

On a blank New Session, switching among Standard, Codex, and Claude selects the matching backend's model group and default reasoning effort. Delayed Codex model discovery is retried, and an older asynchronous result cannot overwrite a newer backend choice.

Forks use the Codex App Server thread/fork method. The child DSH Session sends the inherited parent Thread id and completed lastTurnId; the returned child Thread gets a new durable one-to-one binding. The operation fails closed if provenance is incomplete, the source Thread has no owning DSH Session, or App Server rejects the fork: Relay never falls back to thread/start. Existing persisted bindings are also retained when resume fails. A pending approval is answered only if its DSH Session, Codex Thread, Turn, Item, request, and binding generation still match after reconnect; otherwise it is rejected with diagnostic provenance.

See the reliability specification and executable acceptance matrix. Approval and structured-question composition is defined by the DSH interaction bridge specification.

Plugin Boundary and Relay

This repository was designed and compatibility-tested in Relay, an open-source project for long-running agent work, external-event delivery, reusable DSH workbench views, and multiple conversation backends.

The plugin is independently installable. Its only Relay package dependency is the provider-neutral session import hub, which the package manager installs automatically. It has no runtime dependency on the Relay application, Relay Events, or another feature plugin. It does not replace the official DSH layout or install Files and Terminal views. This separation lets a user install only Codex while the broader Relay project can compose Codex, Claude, events, waits, monitors, and workbench extensions when those capabilities are needed.

Explore or star Relay to follow that broader work: https://github.com/yangbobo2021/Relay.

Update, Inspect, or Remove

Stop DSH Web before changing the bundle, then restart it afterward.

# Show why the plugin is installed
dsh plugin --profile web why relay-dsh-plugin-codex

# Update the npm dependency
dsh plugin --profile web update relay-dsh-plugin-codex

# Remove it
dsh plugin --profile web remove relay-dsh-plugin-codex

Use the npx @deepseek-ai/dsh@0.1.1-rc.2 prefix instead of dsh when you do not have a persistent DSH command.

Troubleshooting

Restart DSH Web. Then run dsh plugin --profile web why relay-dsh-plugin-codex. If pnpm cannot find the package, repeat the npm installation command and read its final error.

The first message reports an authentication or executable error

Run codex login with an official Codex client under the same operating-system user that starts DSH, then restart DSH. The plugin normally uses its bundled official @openai/codex runtime and does not depend on PATH.

If the error says the bundled runtime is missing, update or reinstall the plugin so the package manager restores the platform-specific optional dependency. A managed deployment can explicitly select another native Codex executable:

# macOS or Linux
RELAY_CODEX_COMMAND=/absolute/path/to/codex dsh web

# Windows PowerShell
$env:RELAY_CODEX_COMMAND = 'C:\absolute\path\to\codex.exe'
dsh web

The DSH bundle configuration property codexCommand has higher priority than RELAY_CODEX_COMMAND. Prefer an absolute native executable path; leaving both unset selects the bundled, plugin-tested Codex version.

If Settings shows CODEX_EXECUTABLE_NOT_FOUND, remove an invalid codexCommand/RELAY_CODEX_COMMAND override or replace it with an absolute path. CODEX_RUNTIME_MISSING means the platform optional dependency must be restored by reinstalling the plugin. Connection failed instead means the executable was found but App Server initialization or its process failed.

A forked Session says Rebind required

Normal forks call App Server thread/fork and bind the returned child Thread. This status means the source Thread/Turn could not authorize or complete that operation—for example, the Turn was still running, provenance was incomplete, or the source binding no longer existed. Return to the original DSH Session, fix the reported condition, and retry Fork. The plugin intentionally does not fall back to a fresh replacement Thread.

The composer is disabled

DSH requires a workspace before starting a coding conversation. Select Add workspace, choose a directory, and return to New Session.

An imported Session says the Codex thread is open in another client

Codex permits only one App Server writer for a Thread. Switching to another Thread in Codex Desktop may leave the writer held by that App Server process. Fully quit or restart the owning Codex app, CLI, or App Server process, then retry the message in DSH. The plugin keeps the original one-to-one binding and never creates a replacement Thread. There is no safe force-takeover operation in the App Server protocol. Opening the Session can still synchronize terminal presentation history through thread/read; only continuation is blocked by writer ownership.

git clone https://github.com/yangbobo2021/relay-dsh-plugin-codex.git
cd relay-dsh-plugin-codex
npm install
DSH_ROOT=/path/to/deepseek-harness npm run verify
npm pack

npm run verify runs type checking, tests, and the production build. Boundary tests reject accidental runtime dependencies on Relay or another feature plugin.

Feedback

Report bugs and feature requests in this repository's issue tracker.