What Is DeepSeek Harness (DSH)? The Plugin-Everything Agent Runtime Explained

DeepSeek Harness (DSH) is DeepSeek's open-source agent runtime where everything — models, tools, UI, the agent loop itself — is a plugin. Here's what that means and why 14,000 plugin repos appeared in a month.

Sep 11, 2026DSH Marketplace

On August 13, 2026, DeepSeek open-sourced DeepSeek Harness — codename "Black Whale" — under the MIT license. Its tagline is three words long: "Everything is a Plugin."

Four weeks later, the repository had over 218,000 stars, making it one of the fastest-growing projects in GitHub history, and the dsh-plugin topic had accumulated more than 14,000 community plugin repositories. If you're trying to understand what DSH is and why a plugin ecosystem exploded around it, this is the short version.

A harness, not a model

DSH is not a language model. It's the runtime that agents run on — the layer between a model (DeepSeek's or anyone else's) and the work an agent actually does: reading files, calling tools, managing sessions, rendering a UI.

It's built on the Cordis microkernel, and its defining design decision is that almost nothing is hardcoded:

Model adapters are plugins — swap DeepSeek for another provider without touching the core.
Tools are plugins — file access, shell, web search, vision.
Session and memory management are plugins.
The UI is plugins — the web interface, sidebars, themes.
Even the agent loop itself is replaceable.

This is why the plugin count exploded: in DSH, "plugin" isn't an accessory category, it's the primary unit of everything. Building for DSH means building a plugin.

The two profiles you'll meet

Most users encounter DSH through the web profile (npx @deepseek-ai/dsh web), which serves a browser UI with a Settings surface where plugins appear. There's also a terminal-oriented usage. Plugin commands target a profile explicitly:

dsh plugin --profile web add <package-name>

DSH is a v0.1 developer preview. The README warns plainly that there will be compatibility-breaking changes, and the ecosystem lives on release candidates (0.1.0-rc.x, 0.1.1, 0.1.2-alpha…). Practically: expect plugins to break on upgrades, and prefer plugins that declare their compatible engine range.

Why plugins are both the point and the risk

A DSH plugin executes with the harness's permissions — which are your machine's permissions. An agent runtime that can read your files and run your shell is only as safe as the plugins you add to it. Community marketplaces already flag terminal-surface plugins and block build scripts by default, but "verified" in this ecosystem means "listed", not "audited".

That's the gap this site exists in: we index the plugin ecosystem from live GitHub data, flag what looks off-topic or unmaintained, and review notable plugins against their actual repositories. Start with the plugin directory, the best plugins ranking, or — before you install anything — the safety checklist.

The ecosystem in one paragraph

A month in, the ecosystem already has its own infrastructure: an in-app plugin market (dsh-market), a curated registry (awesome-dsh-plugin), a desktop client, vision bridges, memory layers, and a small but enthusiastic themes scene. It also has the problems young ecosystems always have: tag-spam (about 11% of dsh-plugin-tagged repos are unrelated projects farming visibility), abandoned code, and version churn. We track all of it in our one-month ecosystem review.

DSH Marketplace is an unofficial community project, not affiliated with DeepSeek.