DeepSeek has released an early open-source version of DeepSeek Harness, an agent framework built on the idea that every capability should function as a replaceable plug-in. This matters because AI harnesses increasingly shape how models are used, affecting performance, cost, developer workflows and the difficulty of switching between AI products.

Built on DeepSeek’s Cordis meta-framework, the harness treats models, tools, skills, sessions, sandboxes, storage, scheduling, agent loops and the user interface as configurable components. DeepSeek says developers can select, swap or extend these capabilities without altering the framework’s source code; the accompanying research describes this as dynamic “temporal” and “spatial” composability. The article contrasts harness approaches, noting that different system prompts and design choices can lead the same model to produce different results.