What this site is
DeepSeek Harness in Depth is an independent, source-level walkthrough of the deepseek-harness repository — the open-source agent harness (dsh) built by DeepSeek AI. It is not the official documentation. Where the upstream docs tell you how to use a feature, this site tells you what that feature is made of.
The site is organized into prologue, ten chapters (Parts I–X) and an appendix. Every chapter is built around cited source files under packages/, apps/, native/, vendor/, and docs/, so you can follow along in your own checkout of the repository as you read.
How to navigate
The sidebar mirrors the chapter plan:
| Chapter | Content |
|---|---|
| Prologue | This page |
| Part I · Overview | What dsh is, the plugin philosophy, monorepo anatomy, getting started |
| Part II · Architecture | Boot process, the Cordis extension system, the agent lifecycle |
| Part III · Core Engine | The agent loop, sessions, scopes, system prompts, model selection, tools |
| Part IV · Session & Context | Context sources, compaction, goals, plan mode, human interactions |
| Part V · Capabilities | Shell, filesystem, code runtime, web/search, skills, MCP, LSP, and more |
| Part VI · Orchestration | Subagents, workflow & Ralph, session query & log export |
| Part VII · Security & Sandbox | Sandbox architecture, Landlock, policies, permissions, credentials, guards |
| Part VIII · LLM & Platform | LLM layer, DeepSeek provider, API gateway, storage, hooks, ACP |
| Part IX · Frontend | Client runtime, UI modules, the web frontend, schema forms, localization |
| Part X · SDK & Engineering | SDK protocol/client/server, Typert, testing, CI, vendored libraries |
| Appendix | Package index, glossary, map of official docs |
Start at What Is DeepSeek Harness?, or jump straight to Getting Started to run the thing first.
A word of caution
dsh is in developer preview. The upstream README.md states it plainly:
THERE WILL BE COMPATIBILITY-BREAKING CHANGES.
That means the APIs, config formats, and behavior described on this site are liable to change in future releases. This site is accurate only for the revision it was written against; if you follow along with a newer checkout, expect drift.
License
This site is written from, and cites, the MIT-licensed deepseek-harness repository. The site's own text is community documentation and is not an official DeepSeek AI product. Where this page reproduces a short source excerpt, it is quoted from the upstream MIT-licensed code.
Further reading
- What Is DeepSeek Harness? — the product this site dissects.
- Getting Started — run
dshbefore reading the deep dives. package.json— the root manifest carrying the workspace globs and pinned versions.docs/architecture.md— the upstream architecture document that seeds Part II.vendor/README.md— the manifest for the vendored Cordis framework layer.