--- title: DeepSeek open sources an agent harness where everything... description: DeepSeek open sourced the DeepSeek Harness, a Node.js-based agent runtime released under MIT as a developer preview. Its defining feature is that everything —... canonical: https://daily.dev/posts/deepseek-open-sources-an-agent-harness-where-everything-is-a-plugin-kr4hussbb twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: DeepSeek open sources an agent harness where everything is a plugin | daily.dev og:description: DeepSeek open sourced the DeepSeek Harness, a Node.js-based agent runtime released under MIT as a developer preview. Its defining feature is that everything —... og:url: https://daily.dev/posts/deepseek-open-sources-an-agent-harness-where-everything-is-a-plugin-kr4hussbb og:image: https://api.daily.dev/og/posts/Kr4HUSsbB.png og:image:alt: DeepSeek open sources an agent harness where everything is a plugin og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # DeepSeek open sources an agent harness where everything is a plugin **[The New Stack](https://daily.dev/sources/newstack)** · 5 min read · 0 upvotes · 0 comments ## Summary DeepSeek open sourced the DeepSeek Harness, a Node.js-based agent runtime released under MIT as a developer preview. Its defining feature is that everything — the model adapter, tool registry, session log, and agent loop — is a swappable plugin, built on the Cordis meta-framework. It ships four presets (Standard, Minimal, Code, Creator), an append-only session log powering resume/fork/replay features, OS-level sandboxing (Landlock, Seatbelt, Windows ACL), and support for other providers including Anthropic, OpenAI, AWS Bedrock, Azure, and Gemini. It even bundles subagent bridges to Claude Code and Codex. The repo gained over 33,000 GitHub stars within hours, though DeepSeek currently isn't accepting external pull requests. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is the DeepSeek Harness and how is it licensed? The DeepSeek Harness is a Node.js-based agent runtime that DeepSeek open sourced under an MIT license, available on GitHub as a developer preview. Its distinguishing feature is that everything, including the model adapter, tool registry, session log, and agent loop, is implemented as a replaceable plugin with no privileged core to patch. _Developers evaluating open agent runtimes can track DeepSeek Harness updates and comparisons on daily.dev._ ### What are the four preset modes in the DeepSeek Harness and what do they do? The DeepSeek Harness ships with Standard, Minimal, Code, and Creator presets. Standard gives a full coding agent with filesystem, shell, web search, subagents, and plan mode; Minimal strips it to just bash and str_replace_editor; Code mode generates a TypeScript SDK so the model writes a program instead of making individual tool calls; Creator adds runtime inspection and preset-authoring tools for building custom presets. _Anyone comparing coding agent configurations can follow harness preset details on daily.dev while deciding what fits their workflow._ ### Can the DeepSeek Harness work with models other than DeepSeek's own? Yes, the harness is model-agnostic and its provider catalog includes Anthropic, OpenAI, AWS Bedrock, Microsoft Azure, and Google's Gemini Enterprise Agent Platform, alongside DeepSeek's own endpoint, plus support for custom OpenAI-compatible gateways. It also ships subagent providers to delegate work directly to Anthropic's Claude Code and OpenAI's Codex, both switched off by default and resolved from the host PATH. _Teams weighing which AI models to pair with an agent harness can keep up with provider support changes on daily.dev._ --- Tags: [#open-source](https://daily.dev/tags/open-source), [#mcp](https://daily.dev/tags/mcp), [#deepseek](https://daily.dev/tags/deepseek) [View this post on daily.dev](https://daily.dev/posts/deepseek-open-sources-an-agent-harness-where-everything-is-a-plugin-kr4hussbb) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"DeepSeek open sources an agent harness where everything is a plugin","url":"https://daily.dev/posts/deepseek-open-sources-an-agent-harness-where-everything-is-a-plugin-kr4hussbb","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/deepseek-open-sources-an-agent-harness-where-everything-is-a-plugin-kr4hussbb"},"datePublished":"2026-08-13T17:28:59.043Z","dateModified":"2026-09-14T06:29:40.117Z","description":"DeepSeek open sourced the DeepSeek Harness, a Node.js-based agent runtime released under MIT as a developer preview. 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