Install Node.js
Use a currently supported Node.js release that includes npm and npx.
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.
The normal npm quick-start is short. Use the full operating-system guide if any step fails.
Use a currently supported Node.js release that includes npm and npx.
Run the official npm quick-start command and keep the terminal open.
npx @deepseek-ai/dsh webOpen Settings → Models, save your provider credential, choose a disposable test folder and run one small task.
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.
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 →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 →Choose the one option that matches your situation now.
Choose your operating system, check Node.js, start the local Web UI and run one small test task.
Open beginner setup →Paste or search the exact error, then follow commands written for your operating system.
Search error fixes →See whether an extension is official or third-party, where it appears after installation and what code may run during setup.
Explore extensions →Open the message that matches what you actually see. Each page tells you what to run and what success looks like.
MISSING_CREDENTIALThe current provider has no usable API credential.UNKNOWN_MODELThe selected Model ID is not available under the current provider.401 authentication failedThe remote provider rejected authentication for the current request.EADDRINUSE / EACCES :3080A process is using the port, or Windows has reserved it.Select model / input box disabledThe API credential, workspace or model has not been selected.npm.ps1 cannot be loadedPowerShell blocked the npm or npx script shim.Workspace permission deniedThe operating system or DSH permission setting blocked the file operation.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.
Choose your system so the commands and troubleshooting match your machine.
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 →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 →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 →Add an API credential, choose a test folder, select a model, review approvals and confirm the result on disk.
Official master identifies 0.1.2-alpha.5 at 49a606b.
Open version sources →See where DSH differs from Hermes, Claude Code, Codex and OpenCode before choosing a workflow.
Open agent comparison →Official and third-party describe the source. Install scripts, requested access and review records must still be checked separately.
Review plugin policy →