DeepSeek Harness desktop preview leaks with Apple notarization
A DeepSeek Harness desktop preview leaked to the community between September 25 and 27 and runs cleanly; Mac and Windows builds are available and the product is positioned against OpenAI Aeon and Meta Muse.
DAMO Developer Matrix reported on September 27 that a leaked preview build of DeepSeek’s Harness desktop client was circulated in the community between September 25 and 27 and runs cleanly; the file has been Apple-notarized, signaling that an official launch is imminent. Harness is positioned around cross-application task automation, system-level tool calling, and local deployment, and can complete multi-step complex tasks with deep desktop permissions.
In terms of product shape, the desktop client exposes Standard, PTC, Minimal, and Create modes, and its plugin philosophy is summarized as "Everything is a Plugin," unifying models, tools, and skills as pluggable units. Community developers have already been able to download and run builds on macOS (arm64 and x64) and Windows x64, though DeepSeek has not yet issued any official announcement.
Harness is positioned directly against OpenAI’s Aeon personal assistant, which is expected to be unveiled at OpenAI’s September 29 DevDay, and against Meta’s Muse personal AI assistant. The late-September wave of "AI agent desktop client" launches — including Alibaba’s Qwen Book, DeepSeek Harness, and the Meta Muse Mac app — now forms the three representative shapes of the emerging "AI Agent OS" race.