What changed
DeepSeek Harness v0.2.1-alpha.1 introduces an experimental compatibility layer for Claude Code Mods. The release notes describe its purpose as exploring the overlap between the two extension APIs; they explicitly stop short of promising complete, practical compatibility.
The alpha also adds an entry for asking an agent to create a plugin, optional developer diagnostics, and a configurable public URL for the Web interface. Plugin authors should read the breaking changes: runtime invariant exports are removed, and the old composer statistics extension is split into activity and usage entries. GitHub marks this version as a pre-release.
What it means for your workflow
SaveMyToken editorial take
Treat this as a migration experiment. Check a plugin's actual behavior in a separate test workspace before relying on it for daily work.