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How-to3 min read

DeepSeek Harness (DSH) in Mirasim: on any desktop, next to your other agents

Run DeepSeek Harness (DSH) on macOS, Windows or Linux, next to Claude Code and Codex, with a DeepSeek API key or Mirasim credit. Share sessions with your team.

Mirasim's first-run screen, where you pick and install the coding agents to useMirasim's first-run screen, where you pick and install the coding agents to use

The short answer

DeepSeek Harness (dsh) is DeepSeek's open-source agent harness, released under the MIT license and currently in developer preview. The Mirasim desktop app supports ten agents and runs that same dsh directly. Mirasim is not an official DeepSeek application.

Run on Linux and Intel Mac
Run DSH where there is no official app
Run agents side by side
Run with Claude Code, Codex in one window
Use DSH on your phone
Read and reply when away from your desk
Work with your team
Share one DSH session with your team

Mirasim is useful when you want to run DSH on Linux or an Intel Mac, alongside other agents, on your phone, or in a shared team session.

Three ways to run DeepSeek Harness

DeepSeek's official optionsOfficial desktop app or browser-based dsh web
MirasimDesktop app that runs dsh alongside other agents
Mac, Apple silicon
Official desktop app, or dsh web in your browser
Mirasim desktop app
Mac, Intel
Only dsh web in your browser
Mirasim desktop app
Windows
Official desktop app (64-bit), or dsh web in your browser
Mirasim desktop app
Linux
Only dsh web in your browser (requires Node.js)
Mirasim desktop app
This table compares desktop options across operating systems; Mirasim also has phone apps for Android and iPhone (through TestFlight).

You can download DeepSeek's official desktop app from deepseek.com/en/harness. To use dsh web in your browser, install Node.js and run npx @deepseek-ai/dsh web, which opens the web interface at http://127.0.0.1:3080 on any system that runs Node.js.

Set it up in Mirasim

  1. Install DSH

    Install in Agent Config, or use your npm i -g @deepseek-ai/dsh copy

  2. Choose how to pay

    Use your DeepSeek API key, or Mirasim credit with no DeepSeek account

  3. Start a DSH session

    Pick a model and session mode: Standard, PTC, Minimal or Creative

Setting up DSH takes three steps: after installing, choose billing (DeepSeek bills your own key) and pick DSH as the agent in the composer.

What you get in Mirasim

A DSH sessionRuns in its own window pane, just like any other agent session
  • Run alongside other agentsRun Claude Code, Codex or Kimi Code in the next pane
  • Open web UIOpens the same session inside dsh's own web interface
  • Steer and queue promptsCorrect a running turn, queue prompts, and use your Mirasim MCP servers
  • Continue on your phoneSign in on the phone app to read and reply away from your desk
  • Work with your teamTurn on Share with members to message in one session, signed by sender
This diagram shows what Mirasim adds to a DSH session; Open web UI at the top of the pane keeps DeepSeek's plugin views available whenever you need them.

In any session, you can switch to another agent mid-task and carry the conversation history over. Shared team sessions run on a DeepSeek key shared with members or on space credit, and a team space hosted by Mirasim keeps running after you close your laptop.

Article · Run Claude Code, Codex, OpenCode and seven more coding agents in one app → See the other nine coding agents Mirasim supports, and what running them in one app adds.

Questions

Is Mirasim the official DeepSeek Harness app?
No. DeepSeek's official desktop app is available at deepseek.com/en/harness. Mirasim is a separate desktop app that runs dsh alongside other coding agents.
Can I run DeepSeek Harness on Linux?
Yes. DeepSeek's official desktop app only supports macOS and Windows, but on Linux you can run npx @deepseek-ai/dsh web in your browser or use the Mirasim desktop app.
Do I need a DeepSeek account?
Not when using Mirasim. If you bring your own DeepSeek API key, DeepSeek bills you directly; if you don't have a key, you can run DSH using Mirasim credit.
Which models does DSH run?
DSH runs the DeepSeek V4 model series, including thinking mode. You can choose which model to use for each session.
How much does running DSH cost?
DeepSeek Harness itself is free and open source. When you use your own API key, you pay DeepSeek's standard API rates; for Mirasim's plans and credit pricing, see mirasim.ai/pricing.

Sources

The details about DeepSeek Harness in this article were verified against DeepSeek's official pages on November 8, 2026: deepseek.com/en/harness and github.com/deepseek-ai/deepseek-harness (README and SAFETY.md). Because DeepSeek Harness is changing quickly, please check those pages for the latest information.

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