Tianyi Cui
f6848ee921
Tool changes previously forced prompt consolidation even when the prepared route could activate new tools through history. Rewriting the first system message, or clearing an earlier appended prompt, reset the declaration series and turned additions into immediate declarations. Only routes without toolUpdate need that tool-triggered consolidation. Capable routes append the full changed prompt and keep existing messages. Explicit series starts, surface replacements, and unsupported prompt routes still consolidate; retained-name definition changes still rebuild tool declarations in Session. Cover both update modes and reset paths, and pin the combined prompt/tool transition through the shipped headless profile with shared schema goldens.
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-plugintopic to your plugin repository for discoverability. - Join DeepSeek Harness Discord community.
Contributing
See CONTRIBUTING.md.
Development
Start with the development guide and architecture documentation.
pnpm run dev:web builds, serves, and rebuilds client bundles on source edits in one terminal, and make help lists the matching Make targets for Web and Desktop; the guide's application commands section owns the full table.
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
Third-party dependencies and their licenses are disclosed in THIRD_PARTY_NOTICES.md.