DeepSeek Harness Developer Preview: Everything Is a Plugin

Today, the developer preview of DeepSeek Harness (v0.1) opens for testing to Harness developers worldwide, with its source code released simultaneously under the MIT license.

As an early preview version, many details still need improvement and refinement, and the core plugins and foundational interfaces will evolve rapidly in subsequent iterations. We look forward to hearing feedback and suggestions from the wider Harness developer community.

DeepSeek Harness adopts an "everything is a plugin" design philosophy. We use a plugin-based open architecture to build the Agent Harness: all Agent capabilities—including models, tools, skills, sessions, sandboxes, storage, loops, scheduling, and UI—are composed of plugins that can be freely replaced and flexibly recombined.

DeepSeek Harness is built on the Cordis plugin system, which offers spatiotemporal composability. The Cordis meta-framework is responsible only for loading and unloading plugins and managing their dependencies; all concrete components of the Agent Harness are distinct Cordis plugins. Plugins collaborate with one another through Cordis services and events, and can be freely combined at the configuration layer.

Developers can independently select, replace, or extend any of these capabilities through plugins without modifying the DeepSeek Harness source code itself. This is the most important design principle of DeepSeek Harness: everything is a plugin.