DeepSeek Harness

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DeepSeek Harness (dsh) is an open-source agent harness developed by DeepSeek AI.

It is built on an everything-is-a-plugin architecture and powered by Cordis, whose design is described in _A Programming Paradigm for Spatiotemporal Composability_.

Documentation: https://deepseek-harness.github.io/deepseek-harness/

Developer preview

DeepSeek Harness is in _developer preview_ and iterating rapidly. THERE WILL BE COMPATIBILITY-BREAKING CHANGES.

Review the safety notice before running the project.

Run

Run from npm

Install Node.js, then run:

npx @deepseek-ai/dsh web

The command starts the Web UI at http://127.0.0.1:3080 by default and opens it in the default browser for a local launch. An SSH launch only prints the host URL because the SSH client or editor owns the local forwarded address. Pass --no-open to run the server without opening a browser. See Web UI guide.

Run from source

To run from a repository checkout:

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

pnpm run build prepares the repository artifacts. pnpm dsh web uses those built artifacts without rebuilding.

Community and support

• Submit feedback or bug reports through GitHub Discussions.
• Add the dsh-plugin topic to your plugin repository for discoverability.
• Join DeepSeek Harness Discord community.

Contributing

See CONTRIBUTING.md.

Development

Start with the development guide and architecture documentation.

For agents, follow AGENTS.md.

Citation

@misc{deepseek-harness2026,
  title={DeepSeek Harness: Everything is a Plugin},
  author={DeepSeek-AI},
  year={2026},
  publisher={GitHub},
  howpublished={\url{https://github.com/deepseek-ai/deepseek-harness}},
}

License

MIT

Third-party dependencies and their licenses are disclosed in THIRD_PARTY_NOTICES.md.