Learn DeepSeek Harness

August 16, 2026 · View on GitHub

Get official DeepSeek Harness running, one layer at a time.

Caution

Do not pip-install the unrelated PyPI package deepseek-harness-cli (Henry Zhang). It ships dsh doctor / dsh chat and will steal the dsh name. Official CLI: @deepseek-ai/dsh. Official Python SDK: deepseek-harness-sdk (not pip install deepseek-harness). Check: which -a dsh.

npx @deepseek-ai/dsh web

Then open http://127.0.0.1:3080.

Package: @deepseek-ai/dsh@0.1.0-rc.6 (MIT). One-page commands: QUICKSTART.md.

Philosophy

Agent = Model + Harness. The model is the driver; the harness is the pair of hands.

Everything is a plugin, including the loop. Model adapters, tool registries, session logs, and ctx.agentLoop itself hang on a shared ctx — unload and the registrations retract.

Model-visible means logged. Every line the model sees must be reconstructable from the session log. deriveMessages() projects history from the log; it does not keep a second copy.

Do not fork packages/ to change the loop. Add capability beside it.

Lessons

	Lesson	One line
s01	One loop + bash	`python s01_run_dsh/code.py`; product entry is still `npx @deepseek-ai/dsh web`
s02	Settings → models + Key	Official screenshots; key is write-only, stored at `$DSH_HOME/.credentials.yaml`
s03	Pick a workspace + approve	Composer stays gray until a workspace is selected
s04	First real task	`Summarize this repository and identify its main packages.`
s05	Four presets	standard / PTC / minimal / cordis
s06	Same prompt, minimal vs PTC	Two-tool baseline vs Code Mode composing tools
s07	Headless one-shot	`dsh --profile headless "job"`
s08	Plugins, lightly	`dsh plugin` + topic `dsh-plugin`; installing even one is optional
s09	Official Python SDK	`pip install deepseek-harness-sdk` (not Windows)
s10	Add capability from docs	Official `docs/user/develop/basic`; no source edits, no fake plugins
s11	Everything is a plugin	`ctx.sessions` / `systemPrompt` / `tools` / `agents` / `agentLoop` / `llm`
s12	Profile layers	`dsh-base` is the first layer; later layers replace whole lines
s13	turn / step	Official turn cycle; pre-step; turn-stopping
s14	Session log	Model-visible means logged; deriveMessages
s15	Event gates	waterfall must call `next()`; turn-stopping is serial
s16	Xiaohongshu format plugin	format.mjs + defineTool; source overlay
s17	Plugin config	Schemastery Config, not a plain object
s18	Bundle and install	dsh.bundle vs dsh.profile; prepare and allowBuilds
s19	Three Xiaohongshu notes	Title ≤ 20 characters; course repo link
s20	Preview boundary	Breaking changes coming; do not patch packages

Developer preview. Official wording: THERE WILL BE COMPATIBILITY-BREAKING CHANGES.