# DeepSeek Harness: what it is, what it costs and how to install it

> DeepSeek's open-source agent harness, dsh, is free under the MIT license. You pay for API tokens, from $0.15 per million input tokens on deepseek-flash off-peak.

URL: https://claudegpt.si/news/deepseek-harness-what-it-is-cost  
Published: 2026-11-06T06:54:50.593Z  
Author: ClaudeGPT Si Newsroom  
Section: AI Tools  
Topics: DeepSeek, DeepSeek Harness, AI agents, Open source  
Publisher: ClaudeGPT Si

## Key takeaways

- DeepSeek Harness (dsh) is an open-source, MIT-licensed agent harness from DeepSeek, in developer preview.
- The software is free; usage is billed at DeepSeek API rates, from $0.15 per million cache-miss input tokens on deepseek-flash off-peak (as of November 6, 2026).
- It runs with npx @deepseek-ai/dsh web and needs Node.js and a DeepSeek API key.

DeepSeek Harness, also called `dsh`, is an open-source agent harness from DeepSeek. A harness is the program around a model that lets it work on a project: it reads and edits files, runs commands and keeps a plan. DeepSeek Harness is free (MIT license). You pay only for the DeepSeek API calls it makes. The [GitHub repository](https://github.com/deepseek-ai/deepseek-harness) calls it a developer preview.

## What DeepSeek Harness is

According to the repository README, DeepSeek Harness is built on an "everything is a plugin" architecture and is powered by Cordis, a TypeScript plugin framework. In other words, the parts of the agent are plugins that can be swapped. The README lists the topics `ai-agents`, `cordis`, `dsh` and `dsh-plugin`.

The [Web UI guide](https://deepseek-harness.github.io/deepseek-harness/en/guide/quickstart) says the agent can read and edit files in your workspace, run commands, delegate work and maintain a plan. It asks for approval before operations that need it under the active permission policy.

DeepSeek's [API docs](https://api-docs.deepseek.com/) list Harness under "Agent Integrations," next to tools such as Claude Code and Codex. They describe it as "now in developer preview for agent harness developers worldwide."

## What it costs

The software costs nothing. The repository is MIT licensed. What you spend is API usage, billed by the model you pick. DeepSeek's [pricing page](https://api-docs.deepseek.com/quick_start/pricing/) lists two models, both with a 1M-token context window. Prices are per million tokens in US dollars, as of November 6, 2026.

| | deepseek-flash, off-peak | deepseek-flash, peak | deepseek-v4-pro, off-peak | deepseek-v4-pro, peak |
| --- | --- | --- | --- | --- |
| Input, cache hit | $0.003 | $0.006 | $0.022 | $0.044 |
| Input, cache miss | $0.15 | $0.30 | $0.66 | $1.32 |
| Output | $0.60 | $1.20 | $1.98 | $3.96 |

Peak hours are 01:00 to 04:00 and 06:00 to 10:00 UTC, Monday to Friday, excluding Chinese public holidays. Off-peak prices are half the peak prices. The page also says Search and Fetch are billed at $0.75 per 1,000 successful requests each. The docs do not say whether Harness uses those tools.

Agents send long prompts again and again, so the cache-hit price matters most. A real session's cost depends on how much your project and conversation repeat between calls. The docs give no per-session estimate.

## How to get it

You need Node.js and a DeepSeek API key from [platform.deepseek.com](https://platform.deepseek.com/). Then run:

```
npx @deepseek-ai/dsh web
```

This starts the Web UI at `http://127.0.0.1:3080` and opens it in your browser. Add `--no-open` to skip the browser. To build from source you need pnpm:

```
git clone https://github.com/deepseek-ai/deepseek-harness.git
cd deepseek-harness
pnpm install
pnpm run build
pnpm dsh web
```

These commands come from the README.

Once it is running:

1. Open Settings, then Models, enter your API key and save. The guide says the model route works immediately, without a restart.
2. Click Choose workspace, add your project directory and select it. The session composer stays unavailable until a workspace is selected.

The `dsh` process uses the directory it was started in as its default filesystem location. Other providers and custom OpenAI-compatible endpoints are covered in the project's model configuration guide.

## Risks and what is not settled

The README warns: "THERE WILL BE COMPATIBILITY-BREAKING CHANGES." It also tells users to read SAFETY.md before running the project. An agent that edits files and runs commands should be pointed at a project under version control.

The repository shows no releases at the time of writing. Its page showed about 274,000 stars and a last update on November 4, 2026. Third-party sites quote very different star counts and user numbers,. Pandaily reported a figure of 1.54 million daily users and a coming plugin marketplace. DeepSeek's pages do not say this, though the docs link a plugin market guide.

The Web UI guide covers one mode. It links to a CLI README for other modes.

## Frequently asked questions

### Is DeepSeek Harness free?

The software is free and MIT licensed. It calls the DeepSeek API, which is billed per token, so you pay for the model usage.

### How do I install DeepSeek Harness?

Install Node.js and run npx @deepseek-ai/dsh web. It starts a Web UI at http://127.0.0.1:3080. You can also build it from the GitHub repository with pnpm.

### Is DeepSeek Harness open source?

Yes. The deepseek-ai/deepseek-harness repository on GitHub is MIT licensed.

### Is DeepSeek Harness stable?

No. The README calls it a developer preview and warns of compatibility-breaking changes.

## Sources

- [deepseek-ai/deepseek-harness](https://github.com/deepseek-ai/deepseek-harness), DeepSeek
- [DeepSeek Harness Web UI quickstart](https://deepseek-harness.github.io/deepseek-harness/en/guide/quickstart), DeepSeek
- [Models and pricing](https://api-docs.deepseek.com/quick_start/pricing/), DeepSeek
- [DeepSeek API docs](https://api-docs.deepseek.com/), DeepSeek