Led by Tianyi Cui, who joined DeepSeek in March 2026 from Jane Street.
§2And one promise
There's a setting buried deep in this thing.
the buried setting · shown for real in level two
Level 1 of 3
Install it, understand it, and put it to work.
One command. One key. One folder. One brief.
the three levels · you are here
§3First — what a harness actually is
A model is a brain. Just a brain.
brain + body = agent
§4Why this matters more than people think
A better model moves you a few percent. A better harness changes what's possible.
where the leverage actually is
The model gets the credit. The harness is where the work happens.
§5So what is DeepSeek Harness
It's DeepSeek's body — and they gave it away.
the harness layer, before and after
§6Step 1 and 2 — the only setup there is
Node.js, then a terminal window. That's it.
the whole setup, in three moves
§7Step 3 — the one line that installs it
Type this, press enter, and go make a coffee.
terminal — the entire install
❯ npx @deepseek-ai/dsh web
fetching @deepseek-ai/dsh …
dsh 0.1.0-rc.6 · profile: web
loading 159 plugins …
✓ harness ready → http://localhost:3080
opening your browser…
The real install line.
npx @deepseek-ai/dsh web
The real install on my Mac, ending on the local address it hands you.
§8And here's the smartest choice they made
It doesn't keep you in the terminal. It's a normal web page.
The harness running in a normal browser tab — no terminal in sight.
§9Step 4 — connect a brain
One API key, and the body has something to think with.
Settings → Models: DeepSeek keyed, plus Add provider and Add a custom provider.
§10The door is wide open
Free body. Any brain you like.
one body, any brain
§11Step 5 — give it a workspace
This is the most important habit in the whole course.
the room, and the door you control
§12Step 6 — your first real task
Not a test. A real piece of your actual work.
Read all the notes in this folder. Write a one-page summary of the main points as a new file called summary.md. Use simple language and short bullet points.
The real run: it opens all five notes and writes summary.md. Four steps, thirteen seconds.
§13Why that's different from a chat window
The output is a thing, not a message.
chat window vs harness
§14The pattern for writing good briefs
Look at. Produce. Rules.
the three-part brief
§15Give it real jobs from day one
Three that work immediately.
i.
You make content
Drop your rough spoken notes in the folder. Have it shape them into a clean draft in your voice.
ii.
You're drowning in research
Drop ten saved articles in. Have it pull the twenty facts that matter, with a note on where each came from.
iii.
You run client work
Drop your messy project notes in. Have it produce a clean status summary you could actually send.
§16Now the feature that made me stop and stare
The trajectory view. Every thought, in order, clickable.
The real trajectory — every context row, every tool call, every result, clickable.
§17Why this matters more than it looks
Debugging stops being guessing and becomes reading.
what a failed job gives you
THINKING IT?"This looks like developer stuff — I won't understand a trajectory."
It's a list of steps in order, in plain words: it looked at the folder, it opened this file, it wrote that file.
If you can read a delivery tracking page, you can read this. That's the entire skill.
Once you've managed an agent with X-ray vision, a black box feels like an employee who won't tell you what they did all day.
§18One more level-one tool
Export any session as a complete log.
what an exported session log holds
❯ session log ↓ — Summarize folder notes into summary.md
turns: 1 steps: 4 LLM: 13.8s tool calls: 0.2s
TTFT avg 0.7s · 156 tok/s · cache hit 77%
input 59.9K tok · output 1.7K tok
✓ every prompt, tool call, argument and result — saved
you review the trajectory the way a manager reviews a report
The real numbers from the run in this course, straight off the bottom bar of my session.
§19Now the honest print on the box
This is version 0.1. A developer preview.
Wire your whole operation to it this week
you get burned
Treats a v0.1 preview as finished software
Breaking changes land between versions
Plugins break, then get fixed a month later
You find out at midnight
No fallback when it moves
Real jobs, not sole custody
you get the upside
Give it real work from day one
Keep proven agents on the critical path
Everything it makes lands in a folder you can check
Every step is in the trajectory
It earns more responsibility as it stabilises
§20That's level one complete
Here's what you've got if you stop right now.
i.
One command installs it
And it runs as a normal web page on your own machine.
ii.
One key connects the brain
DeepSeek, OpenRouter, or a free local model. Your choice, one dropdown.
iii.
One folder is the room
It works there, and it can't touch anything else.
iv.
Plain-English briefs
Look at, produce, rules. No magic prompts needed.
v.
Full trajectory vision
Every thought and every step, clickable, in order.
The plugin system, the four modes, and creator mode.
Where the interface becomes clay you shape by typing a sentence.
the three levels · you are here
§21Start with the headline on their own GitHub page
Three words: everything is a plugin.
The plugin list on my install. The counter reads 159.
§22Here's the picture to hold in your head
A sealed car, versus a car whose parts pop out while it's driving.
sealed product vs swappable organs
§23And better parts is not a hope
The community moved within hours of launch.
community plugins by category · 300+ indexed in the first days
§24Under the hood this runs on something called Cordis
Every action in the system can be cleanly reversed.
why the modularity doesn't fall over
§25Now the four modes
The control panel most people click past on day one.
the power ladder · four built-in presets
All four built-in modes, with DeepSeek's own descriptions.
§26Creator mode — the part that doesn't feel real
You describe a tool you wish existed. It builds it.
Add a small panel in the bottom corner of the interface that shows my three tasks for today, and let me tick them off.
The real creator-mode run: one sentence in, a working plugin out.
§27Then you click approve
And the thing you described appears on your screen. Working.
I click approve and the panel appears, bottom right, ticking.
THINKING IT?"There's no way that's building real software from one sentence."
It built a UI panel plus a small service to save the tick state per day, and asked permission before running any of it.
The video above is one continuous real session on my machine — the sentence I typed is in the code block on the section before it.
§28And it's a conversation, not a one-shot
Don't like it? Say so.
iterate by talking
Every piece of software you have ever used was somebody else's guess about what you need.
§29Think about what that actually changes
The interface stops being fixed and becomes clay.
i.
A content pipeline panel
Tracks each piece from idea to published. Describe it, approve it, use it.
ii.
A one-click morning routine
A button that kicks off your research run before you've finished your coffee.
iii.
A last-five-outputs board
A small dashboard showing what your agents produced while you were out.
§30Now the buried setting I promised
Switch off any part of the product itself — with a text file.
~/.dsh/profiles/web/cordis.patch.yml
# Your patch layer for this dsh profile, applied after every bundle layer.
❯ - id: ui-sidebar
disabled: true
# save the file, reload the page — the sidebar is gone.
# delete the two lines, reload — it's back. nothing else breaks.
✓ real file on my machine. on this build it's cordis.patch.yml
The real file and the real two lines.
My live install: two lines saved, the sidebar vanishes, then comes back.
§31Is editing a text file a bit raw?
Yes. And I'm showing you anyway, for two reasons.
why the buried setting matters
§32Next — models and money
This bit pays for the time you're spending on this course, many times over.
what the same day's work costs, depending on where you point it
§33So here's the two-model pattern to steal
Strong model plans. Cheap model executes.
the architect and the crew
§34And the third option
Ollama runs open models on your own computer. Nothing leaves it.
the fully private setup
§35Last piece of level two
The quiet line in the repo that matters more than the whole launch.
one instruction file, every agent
§36If you don't have one yet, start today
The highest-leverage twenty minutes in this entire course.
~/.dsh/AGENTS.md — the real file on my machine
❯ # Workspace instructions — Julian Goldie's Agent OS
## Who this is for
- Runs an SEO agency and the AI Profit Boardroom.
- Output is read by business owners, not engineers. Plain English.
## House rules
- Never fabricate numbers, quotes, testimonials or results.
- Never print API keys, tokens or .env contents.
- Builds go in the folder you were given — never scatter into $HOME.
## Style
- British English. Short sentences. No hype words.
✓ read automatically at the top of every single session
You brief once, in writing, forever — instead of re-explaining yourself in every session for the rest of your life.
The harness reading my AGENTS.md at the top of the session.
§37And notice what DeepSeek chose here
They built for compatibility instead of lock-in.
what transfers to DeepSeek Harness on day one
If every agent on your machine reads the same files and speaks the same protocols — why are you running them separately at all?
Level 3 of 3
The Agent Operating System, with DeepSeek Harness inside it.
Every agent a tile. One shared memory. Work that runs while you're at the gym.
the three levels · you are here
§38The problem
The Falling Behind Problem.
the treadmill picture in your head
THINKING IT?"I've barely learned the last tool. I can't take on another one."
You're not taking on another tool. You're building one system that new tools plug into.
When you have the system, a new tool isn't homework — it's a free upgrade delivered to your door.
§39That feeling is built on a picture that's wrong
You don't keep up with the tools. Your system absorbs them.
the reframe
§40Let me show you what that looks like
One dashboard. Every agent a tile, side by side.
Mission Control on my machine — every agent a tile.
§41And here's DeepSeek Harness living inside it
Same harness. Same workspace. One tab over from everything else.
The DeepSeek tab in my Agent OS, switched to Harness mode.
§42The thing that makes it a system
One shared memory. A folder of plain text notes.
the shared brain
The real vault every agent on the board reads and writes.
§43Here's how to structure yours
Keep it simple. Complicated vaults die.
~/Obsidian Vault — the entire structure
❯ AGENTS.md
↳ your business, your rules, your voice — read by every agent
01 Daily/
↳ what happened, what's in progress
02 Projects/
↳ one note per active project, with its current state
03 Research/
↳ everything the agents gather overnight
04 Output/
↳ drafts and finished work, ready for you to check
Five folders and one instruction file.
§44Now watch the pieces move across a real day
The system does not pause because you stepped away.
one day, three agents, one vault
You've stopped being the person who does every step. You're the one who directs the system and reviews the output.
§45So where exactly does it fit in the lineup?
Three roles, and they're specific.
the three jobs it does on my board
§46And here's how the modular design pays off at system level
One organ upgraded. Whole body stronger.
swap one part, the whole system improves
§47Now the honest section
Preview software gets real jobs — not sole custody.
how much of my board DeepSeek Harness owns today
§48Two doubts left
Three beliefs to drop before you start.
These are the exact doubts that keep smart people watching from the sidelines for years.
Wrong: "This is developer stuff. I'm not technical."
Right: You typed one command. A normal web page opened. You typed English sentences describing work, clicked approve, and read a visual timeline of steps. The paper, the protocols, the architecture — you never touch any of it, the same way you drive a car without understanding the engine.
Wrong: "I'll wait until this settles down."
Right: Wait a year and the learning curve is the same height — you'll just climb it with a year less practice. The people who look effortless on version three are always the ones who wrestled with version zero point one.
Wrong: "Another tool means another thing to keep up with."
Right: The instruction files, the shared vault, the skill of writing a clear brief, the habit of checking a trajectory — all of it transfers to whatever ships next. You learned the system, not the tool.
“Doesn't running an Agent OS burn a fortune in tokens?”
where the work actually runs on my board
§50Let me land the whole course
Three levels, in one screen.
Level 1
You stopped copy-pasting
One command installs it, one key connects the brain, one folder is the room. Plain-English briefs — look at, produce, rules. The output is a real file.
Level 2
You stopped waiting for developers
Everything is a plugin — interface, tools, memory, the loop. Creator mode builds custom tools from one sentence. One text file switches off any organ. Two-model pattern cuts the cost to almost nothing.
Level 3
You stopped doing every step
It takes its place as a tile next to Claude, Hermes and OpenClaw, all sharing one vault. Agents work overnight and hand results to each other. You direct and review.
§51Step back and see what actually changed
Access stopped being the thing that separates businesses running agents from businesses that aren't.
