deepseek-ai/deepseek-harness is an open-source agent harness built by DeepSeek. The repository description reads 'Everything is a Plugin', presenting a structure where tools and skills are attached as plugin units. There is no official release yet, so no published version is available. The repository lists TypeScript and an MIT license.
A harness is the foundation that supports an agent by connecting tools and capabilities to perform tasks. This project layers a plugin structure on top of Cordis. Cordis is a programming paradigm dealing with spatial and temporal composability. The package structure is divided into independent modules such as acp, browser-use, computer-use, compaction, context, guard, lsp, mcp, and plan. The web interface is launched with an npx command, and the default port is 3080. There are two installation paths: the npm distribution and a source build.
That said, the README states that it is at a developer preview stage and warns that compatibility-breaking changes are frequent. There is also a separate safety notice document. The repository includes benchmarks covering stream replay and continuous agent runs, but the README body does not present any measured figures. There is therefore insufficient grounds to say performance or stability has been proven, and it is more appropriate to view the current implementation as experimental.