Analyzing DeepSeek Harness: How Do You Build an Agent Harness Where "Everything Is a Plugin"?
DeepSeek Harness (dsh) turns the model adapter, the tool registry, the session log, and even the agent loop into Cordis plugins, then assembles the product by stacking patch layers on top of an empty tree. Two weeks after release it passed 200k GitHub stars. This is a source-level analysis of its kernel (Cordis), profile and bundle composition, the rule that the session log is the source of truth, capability seams, self-modification tools, and the way it runs Claude Code and Codex as subagents.