Install DeepSeek Harness on Windows 11 + Run DeepSeek V4 (2026)

Written guide, kept updated with fixes from the comments: https://liteailab.com/install-deepsee... Install DeepSeek Harness on Windows 11 and run DeepSeek V4 through OpenRouter — one command, a few cents, no subscription. This is the full setup, start to finish, on a stock Windows 11 PC. DeepSeek Harness isn't a model. It's the scaffolding that runs one: what the model remembers, what it's allowed to run, when it stops. Get that layer right and the same model gets noticeably smarter. In this guide we install it with npm, connect DeepSeek V4 Flash through OpenRouter, add a workspace, and build a working Kanban board — then read the receipt: the whole build costs less than a cent. After that, Trajectory (every step it took, on the record), PTC mode, Creator mode (the harness builds a feature into itself), and an honest section on what's not ready yet before you move real work onto it. Beginner-friendly. No WSL, no source build, no DeepSeek platform account needed. WHAT YOU NEED Windows 11 Node.js 24 or newer (22.19+ also works) — install video below An OpenRouter account with a few dollars of credit THE COMMANDS (Windows Terminal / PowerShell) Check Node.js: node --version Install the harness once, for the whole PC: npm install -g @deepseek-ai/dsh Make the demo folder: mkdir kanban-board Start the harness (from any folder): dsh web The Web UI opens at http://127.0.0.1:3080 — your own PC, nothing reachable from outside. Model ID to type under Settings → Models → OpenRouter → Customized settings: deepseek/deepseek-v4-flash-0731 Update to the newest release later (read the Releases page first): npm install -g @deepseek-ai/dsh@latest The three prompts used in the video (Kanban board, PTC mode, Creator mode) are in the pinned comment, ready to paste. CHAPTERS 0:00 DeepSeek Harness isn't a model 0:59 Why the harness matters: same model, 18 points apart 1:36 Install DeepSeek Harness (Node check, npm install, dsh web) 2:57 First run: the notice and the API key dialog 3:35 Get an OpenRouter key and add credits 4:03 Settings → Models: add OpenRouter and DeepSeek V4 Flash 5:13 Choose workspace (the dialog opens behind the browser) 5:40 Pick the OpenRouter model and permissions 6:09 Build the Kanban board 7:05 Test it: add a card, drag it, reload 7:20 What it cost: the stats bar and OpenRouter Activity 7:54 Trajectory: every step it took 8:19 Inspect a step and export the session log 8:57 PTC mode: one program instead of many round trips 10:18 Standard vs PTC: steps and tokens compared 10:49 Creator mode: everything is a plugin 11:51 Approve the plugin: a live clock in the sidebar 12:18 The catch: reload and it's gone 12:48 Before you move real work here: developer preview 13:35 The harness doesn't make the model smarter 14:05 Wrap up WATCH NEXT Rather run this on a free model? The custom provider form points straight at OmniRoute: Claude Code + OmniRoute: Run It Free on Windows 11 (2026)    • Claude Code + OmniRoute: Run It Free on Wi...   MENTIONED IN THIS VIDEO Node.js not recognized? Set it up here first: How to Install Node.js & npm on Windows 11 WITHOUT Errors (2026)    • How to Install Node.js & npm on Windows 11...   OFFICIAL LINKS DeepSeek Harness on GitHub (read the Developer preview notice) https://github.com/deepseek-ai/deepse... Releases — check before every update https://github.com/deepseek-ai/deepse... DeepSeek V4 Flash on OpenRouter (pricing and model ID) https://openrouter.ai/deepseek/deepse... OpenRouter API keys https://openrouter.ai/settings/keys OpenRouter credits https://openrouter.ai/settings/credits OpenRouter Activity — your spend per request https://openrouter.ai/activity ──────────────────────────────────────── GOOD TO KNOW (details in pinned comment) Nothing happens when I click Choose workspace: a Windows folder dialog called Select Workspace Directory opened behind the browser. Click it in the taskbar. Bottom right says DeepSeek V4 Flash but requests fail: that's DeepSeek's built-in provider, not your key. Click the model, then Model, and pick DeepSeek V4 Flash under openrouter. No web search tool: web search needs a DeepSeek API key. It isn't available on an OpenRouter-only setup. The Kanban build doesn't need it. The plugin from Creator mode disappeared after F5: expected today. Creator-built plugins live in the browser tab until you save them by hand as a package on disk. Can I use a ChatGPT or Claude subscription? No. The harness connects to models through API keys, not chat subscriptions. Subscribe if you want dev and AI tools set up properly on Windows 11. That's what we do here. 🧰 The hosting & tools I actually use: https://liteailab.com/deals (affiliate links — cost you nothing extra) 🌐 All written guides: https://liteailab.com/