Install DeepSeek Harness: check Node.js, run npx dsh web

To install DeepSeek Harness for the first time, follow four steps: check Node.js, start it with npx, verify the install, then add your first plugin.

Overview

DeepSeek Harness (command-line tool dsh) is the open-source agent harness built by DeepSeek AI, and the official way to install and start it is one command: npx @deepseek-ai/dsh web. It downloads and launches everything, serving the Web UI at http://127.0.0.1:3080 by default and auto-opening it in your browser on a local machine (source). This guide breaks each step down for beginners so you can complete your first install by following along.

Before installing DeepSeek Harness: make sure Node.js is ready

The npx startup of DeepSeek Harness depends on exactly one prerequisite: Node.js on your machine. Spend a minute checking first — it prevents most errors later.

1. Open a terminal and run node -v; it should print a version number such as v20.11.0;
2. Run npm -v; it should print an npm version — npm is bundled with Node.js, no separate install needed;
3. If you see node: command not found: download and install the official LTS package from the Node.js website, reopen the terminal, then repeat step 1;
4. (If your network is slow) confirm npm can reach its registry — you may run npm config set registry https://registry.npmmirror.com first to avoid a stalled first download.

Once these checks pass, you are ready to install DeepSeek Harness itself.

Install and start DeepSeek Harness: bring up the Web UI with one npx command

The officially recommended way to start is the install-free npx run: it writes no global files and downloads, initializes and starts in one command. The command and full description live in the run section of the official README.

1. Run the startup command in your terminal:

npx @deepseek-ai/dsh web

2. The first run downloads the @deepseek-ai/dsh package and initializes the default web profile — wait for the terminal to report that the service has started (downloads may take tens of seconds to minutes depending on your network);
3. On a local machine the browser opens http://127.0.0.1:3080 automatically; if it does not, type the address manually;
4. Seeing the DeepSeek Harness Web UI means startup succeeded — keep this terminal window open; closing it stops the service;
5. To run the server without opening the browser, add --no-open: npx @deepseek-ai/dsh web --no-open.

For long-term daily use or tracking the latest development build, you can also install globally with npm (then run dsh web directly) or build from source. The full comparison and commands for both are in our install guide for the three install methods. Switching methods never loses data — your config and sessions live under the default ~/.dsh directory regardless of the install method.

Verify DeepSeek Harness: the page opens at 3080

The success bar is: the service starts and the page opens. Run the checks below in order; when each shows its expected result, your first install is complete.

1. Look at the terminal that started it: it should report the service is listening on http://127.0.0.1:3080 without errors;
2. Open http://127.0.0.1:3080 in a browser: you should see the DeepSeek Harness Web UI home page (with the npx method this is the verification entry — it does not create a global dsh command);
3. If you switched to the global npm install, additionally run dsh --version and it should print a version number;
4. Finish the first-time setup shown on the page, such as configuring a model provider (a DeepSeek API key or a local model both work), then send a message to confirm the conversation works.

At this point DeepSeek Harness itself is installed and running.

Next step: install your first DSH plugin from the plugin market

Once the core runs, extending capabilities means installing plugins — a visual market beats memorizing commands. For one-stop browsing, installing, updating and uninstalling plugins, install the community-official DSH Plugin Hub plugin market:

1. Install the DSH Plugin Hub plugin into your current environment from the Web UI, then reopen it from Settings → Plugin market;
2. In the Market screen, search or browse categories; each plugin card shows the name, version, verified badge and description;
3. Clicking Install first shows a confirmation dialog with the plugin name, source repo and the command that will run — the install only starts after you confirm, a safety gate before anything executes;
4. After it finishes, manage the plugin in the Installed list, where future updates and uninstalls are one click away.

Instead of memorizing dsh plugin flags, manage your plugins through DSH Plugin Hub's visual interface — search, install, update and uninstall all come with confirmations and progress hints, and official catalog entries are marked as verified. Visit https://dsh-plugin.org/ for details.

Sources: deepseek-ai/deepseek-harness, DeepSeek Harness official docs - Quickstart, dshplugin/dsh-plugin-hub