How to Build a DeepSeek Harness Plugin: A Step-by-Step Tutorial

Building a DeepSeek Harness plugin is surprisingly quick: the framework’s everything is a plugin design means a useful plugin can be a single file. This tutorial takes you from zero to a working plugin.

What you need

• Node.js 18+ (DeepSeek Harness is a Node runtime)
• DeepSeek Harness installed (npm install -g @deepseek-ai/dsh)
• A GitHub account (for publishing)

Step 1 — Scaffold the project

Create a folder and initialize:

mkdir my-dsh-plugin && cd my-dsh-plugin
npm init -y
npm install @deepseek-ai/dsh-plugin-kit  # or the current SDK package name

The plugin development kit provides types and helpers. Check the official template repository for the current package names — the ecosystem moves fast.

Step 2 — Write the plugin manifest

Every plugin declares itself with a manifest (plugin.json or in package.json):

{
  "name": "my-dsh-plugin",
  "version": "0.1.0",
  "description": "Adds a focused capability to DeepSeek Harness",
  "capabilities": ["tool"],
  "license": "MIT"
}

The capabilities field tells the harness what your plugin provides: tool, skill, memory, theme, workflow, integration, and so on.

Step 3 — Implement a capability

A minimal tool plugin exposes a function the agent can call. In TypeScript:

import { defineTool } from '@deepseek-ai/dsh';

export const helloTool = defineTool({
  name: 'hello',
  description: 'Returns a greeting for the given name',
  schema: { name: { type: 'string' } },
  run: async ({ name }) => `Hello, ${name}!`,
});

Register it in your plugin entry point, and the harness exposes it to the agent automatically.

Step 4 — Test locally

dsh plugin add ./my-dsh-plugin   # install from a local directory
dsh plugins list                 # verify it loads
npx @deepseek-ai/dsh web         # test in the web UI

The local install loop is the fastest way to iterate: change code, re-add the plugin, test again.

Step 5 — Write a README and publish

A good README is part of the plugin:

• What it does (one paragraph)
• How to install (dsh plugin add github:you/my-dsh-plugin)
• What it needs (permissions, other plugins)
• License

Then push to GitHub and tag the repository with the dsh-plugin topic. That’s how the ecosystem discovers it — and how curated directories like this one find it for listing. You can also publish to npm for dsh plugin add @scope/package installs.

Step 6 — Submit it

Once published, submit your plugin to this directory so the community can find it.

Design tips from the ecosystem

• One focused capability per plugin — the best plugins do one thing well (see the directory for examples).
• Document the safety surface — if your plugin runs code or makes network calls, say so in the README. Trust is a feature.
• Pin and version — version your releases and let users pin commits.
• Listen to issues — active maintenance is a ranking factor in community directories and a trust signal for users.

Next steps

• Read the safety guide to understand what your plugin can access.
• Study how installation works from the user side.
• Check the development tools in the Development & Runtime category for SDKs and helpers.

The DeepSeek Harness plugin ecosystem is young, which means there’s still room for the plugin you want to build.