Tianyi Cui
29f7e7bdf5
Native V4 admission and Session adoption reject every request/header.header.system field because system prompts belong to system/message events. EpochHeader omitted that key, so the generated schema classified adding optional system text as a same-version optional-property addition even though released readers would reject it. Declare system?: never with the shared persistenceReserved marker so the schema records the existing prohibition. Widening the field to string now changes a forbidden value set and requires a version bump. Keep both runtime guards and all unknown-metadata handling unchanged, and document the reservation alongside the current header type and V4 acknowledgement. The regression extracts the actual event:request/header schema, checks the optional-never field, widens only that property, and verifies the version-bump diagnostic and native refusal. It fails without marker extraction and passes with the shared tooling support. The focused reservation, retired-syntax, and Session surface suites pass 65 tests; all 436 type-equiv blocks match their source. Generic marker extraction belongs to the foundational tooling change.
DeepSeek Harness
English | 中文
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.
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.