DeepSeek has released an agent harness.
It is called DeepSeek Harness v0.1. It is still a developer preview.
It was announced on the night of August 13, 2026. The announcement channel was DeepSeek's official X account.
The codebase is public on GitHub under the MIT license.
At release, the star count was mentioned as 24,000. By the time of research, it had grown to more than 78,000.
Where Did the "Everything Is a Plugin" Design Come From?
This harness runs on the Cordis framework.
Cordis is not DeepSeek's own technology.
Judging by its official repository, it belongs to the external open-source family. DeepSeek built the harness on top of it.
Everything from the model to the UI is built as plugins.
Models, tools, sessions, and sandboxes are all covered. Combining, swapping, and extending are the basic assumptions.
Change the Model Without Rewriting the Code
Agent harnesses are normally a hassle to build.
Every time you change a model or tool, you have to rebuild the structure.
DeepSeek Harness's answer is simple.
You only need to swap the plugin. The rest of the structure can stay as is.
The repository also includes a web app built on React 18.2. You can extend even the agent UI in the same structure.
It favors teams experimenting with many model and tool combinations. Plugin-level swapping can cut development costs.
The v0.1 API May Change
It is still a developer preview. In the release version, the API may change.
The original X post has no images or video.
The only evidence is GitHub and the official announcement.
Before adopting it, check the Cordis update cadence.
You should also read the license terms yourself.