Install Node.js
Use a currently supported Node.js release that includes npm and npx.
Independent, source-backed DSH guide
Install, troubleshoot, and extend DeepSeek Harness
DeepSeek Harness (DSH) is an open-source agent harness: connect a model provider, work with local files, and add plugins and MCP. Start with installation, or find the fix for your exact error.
DSH Desktop for Windows and macOSPrefer a desktop app over terminal setup?
Use the community-maintained desktop wrapper to manage the local Harness process in a dedicated window. Review compatibility and safety notes before downloading.
See Desktop compatibility and setup →Third-party desktop app · Community-maintained, not an official DeepSeek product. The app does not include API credit.
Install DeepSeek Harness in 3 steps
Run the official npm quick-start directly from this page. Copy the command here; use the full operating-system guide if any step fails.
Launch the local Web UI
Run the official npm quick-start command and keep the terminal open.
npx @deepseek-ai/dsh webConnect a model and test
Open Settings → Models, save your provider credential, choose a disposable test folder and run one small task.
What is DeepSeek Harness (DSH)?
DSH is the open-source agent harness around a model: it connects model selection, sessions, tools, workspace access, approvals and plugins into an executable workflow.
What DSH actually adds
A model produces model output. DSH supplies the runtime around it: a selected provider and model, a workspace, session history, tool execution, approval boundaries and plugin-composed capabilities.
Read the DSH overview →DSH vs Claude Code
Claude Code is a Claude-centered coding agent product. DSH is positioned as a plugin-first harness you can reshape across providers, tools, Web UI surfaces, MCP, skills, subagents and workflows.
Compare agent workflows →What are you trying to do?
Choose the one option that matches your situation now.
Install DSH for the first time
Choose your operating system, check Node.js, start the local Web UI and run one small test task.
Open beginner setup →
Fix a specific error
Paste or search the exact error, then follow commands written for your operating system.
Search error fixes →
Add plugins, MCP or providers
See whether an extension is official or third-party, where it appears after installation and what code may run during setup.
Explore extensions →Common DSH errors
Paste the exact terminal error below. The matching result expands the fastest next step here, with a command to copy when one is available.
You can paste a full terminal error line. Search runs locally in your browser, and the text you enter is not uploaded.
Showing 7 common fixes first; search to reveal the matching answer from all 11
MISSING_CREDENTIALCredentials
MISSING_CREDENTIAL Error
Save a credential for the provider used by the current DSH session, then select a valid model and retry.
UNKNOWN_MODELModels
UNKNOWN_MODEL Error
Select a model ID that actually exists under the configured provider, or add that model before retrying.
401 authentication failedCredentials
401 Authentication Failed
Check the key, provider Base URL and any environment-based credential, then test model discovery separately from chat.
EADDRINUSE: address already in use 127.0.0.1:3080Installation
EADDRINUSE: address already in use 127.0.0.1:3080
Identify the process using port 3080 or a Windows reserved-port conflict, then stop only a confirmed stale process or use another port.
127.0.0.1:3080 does not openWeb UI
127.0.0.1:3080 Not Opening
Check whether DSH is running locally or on a remote server, then open the exact printed URL or create an SSH port forward.
'node' is not recognizedInstallation
'node' Is Not Recognized
Install a supported Node.js version, reopen the terminal to refresh PATH, and verify Node before starting DSH.
npm / npx is not recognizedInstallation
npm / npx Is Not Recognized
Repair the Node.js installation or PATH until node, npm and npx all work in the same terminal.
Install for your operating system
Choose your system so the commands and troubleshooting match your machine.
Windows
Windows 10/11 setup with Node.js, PowerShell and the official npx quick-start, plus npm.ps1 and port 3080 troubleshooting.
Open Windows installation guide →
macOS
Install Node.js, launch the local DSH Web UI with npx, configure a model and run your first workspace task on Intel or Apple silicon Macs.
Open macOS installation guide →
Linux
Use nvm or your existing Node.js environment, launch DSH with npx, and handle local versus remote-server access to the Web UI.
Open Linux installation guide →See the Web UI workflow before you start
Add an API credential, choose a test folder, select a model, review approvals and confirm the result on disk.
Latest verified source
Official master identifies 0.1.2-alpha.5 at 49a606b.
Open version sources →Compare agents
See where DSH differs from Hermes, Claude Code, Codex and OpenCode before choosing a workflow.
Open agent comparison →Plugin checks
Official and third-party describe the source. Install scripts, requested access and review records must still be checked separately.
Review plugin policy →