The deciding difference is operational: DeepSeek Harness can run on infrastructure you control, Claude Code cannot. If that constraint is real for you, it settles the choice before anything else is considered.
Anthropic's coding agent — terminal, IDE and SDK, with hooks, skills and MCP built in.
Configure via .claude/settings.json; drop reusable procedures in .claude/skills/.
Everything is a plugin — the model adapter, the tool registry, the sandbox and the agent loop itself are all swappable.
Web UI first — `dsh web` serves on 127.0.0.1:3080 rather than taking over the terminal. Built on Cordis. Still a developer preview: DeepSeek warns of compatibility-breaking changes, so pin the version.
| Claude Code | DeepSeek Harness | |
|---|---|---|
| Licence | Proprietary | Open source |
| Pricing | paid | open source |
| Self-hostable | No | Yes |
| Languages | Any language | TypeScript |
| Install | npm install -g @anthropic-ai/claude-code | npx @deepseek-ai/dsh web |
| Keys required | ANTHROPIC_API_KEY | None |
The deciding difference is operational: DeepSeek Harness can run on infrastructure you control, Claude Code cannot. If that constraint is real for you, it settles the choice before anything else is considered. Claude Code: Anthropic's coding agent — terminal, IDE and SDK, with hooks, skills and MCP built in. DeepSeek Harness: Everything is a plugin — the model adapter, the tool registry, the sandbox and the agent loop itself are all swappable.
Claude Code is a hosted service only. DeepSeek Harness can run on your own infrastructure.
Claude Code is proprietary (paid). DeepSeek Harness is open source (open source).
Every page here answers to Accept: text/markdown and returns the same content at roughly a tenth the tokens. No separate site, no toggle — same URL.
curl -s -H "Accept: text/markdown" https://newagent.build/compare/claude-code-vs-deepseek-harness