On August 13, DeepSeek released the developer preview of Harness v0.1 and open-sourced it under the MIT license. The Harness adopts a 'everything is a plugin' architecture, allowing models, tools, and the agent loop to be replaceable, aiming to provide an assemblable agent runtime foundation.
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On August 13, DeepSeek released Harness v0.1 developer preview, open-sourced under the MIT license. Its core design is 'everything is a plugin,' from models to the Agent Loop, all replaceable, but multi-agent orchestration remains hierarchical Supervisor-Worker, not reaching Swarm level.
On August 13, DeepSeek opened the DeepSeek Harness developer preview to global developers, with the first version v0.1, and simultaneously open-sourced the code under the MIT license. Developers can launch the Web UI via npx @deepseek-ai/dsh web, or pull the full project from GitHub. DeepSeek explicitly stated that many details still need polishing, and core plugins and basic interfaces will iterate rapidly in the future.
Harness is positioned as an 'assemblable Agent runtime base,' distinct from feature-fixed Coding Agents. It targets Harness developers, not ordinary users who just want to download a client to write code.
DeepSeek Harness pushes plugin boundaries down to the entire runtime: models, tools, skills, sessions, sandbox, storage, Agent Loop, scheduling, and UI are all composed of plugins. Supporting this architecture is the Cordis plugin system, which only handles plugin loading, unloading, and dependency relationships. Specific Agent capabilities are provided by different plugins, which collaborate via services and events.
Tool calls are broken into an extensible pipeline: before execution, they pass through hooks, approval, permission checks, sandbox, and timeout control; after execution, results can be rewritten, recorded, and rendered in the UI. In PTC mode, code and its sub-calls also go through this pipeline, unable to bypass approval and sandbox.
The four run modes (Standard, PTC, Minimal, Creative) are based on the same foundation, differing only in the default set of loaded plugins. Creative mode allows the Agent to inspect the runtime, experiment with Cordis plugins in memory, and combine new modes, making configuration itself an object the Agent can operate on.
This article is based on InfoQ reporting, which is industry media coverage, not an official DeepSeek announcement. Details about architecture and mode descriptions are from the report's retelling, not independently verified against official documentation. Some judgments (such as 'paradigm unchanged') are the author's opinions and are inferential.
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