DeepSeek Harness is an open-source agent harness built on an everything-is-a-plugin architecture powered by Cordis.
The tool addresses the challenge of building extensible agent systems by treating all components as plugins that can be composed together. Its plugin-based design allows developers to add functionality modularly without modifying core code, leveraging Cordis's spatiotemporal composability paradigm to manage how plugins interact across time and space.
Developers should adopt this tool if they are building agent applications that require flexible, composable architectures where features can be added and removed dynamically. It suits projects where extensibility and plugin-driven development are priorities. The tool provides a Web UI for interaction and can be run either from npm or from source, with development workflows supported through build and watch commands.
The project is in developer preview with rapid iteration and compatibility-breaking changes expected. Development activity shows active maintenance with documented guides for both users and contributors, including separate documentation for development setup, architecture, and agent-specific implementation. The project maintains community engagement through GitHub Discussions and a dedicated Discord community, with a plugin discovery mechanism via GitHub topics.
