Using with Other Tools
harness-kit plugins are plain markdown — no binaries, no runtimes, nothing to compile. Any tool that reads prompt files or instruction markdown can use the workflows. The primary distribution path is Claude Code's plugin marketplace, but the content works anywhere.
Open Standard
The skill format used by harness-kit follows the Agent Skills specification — an open standard for cross-platform skill portability. Skills built to this spec work in Claude Code, GitHub Copilot, and any other compliant platform without modification. The sections below show how to wire harness-kit skills into each tool.
GitHub Copilot
Native plugin install (Copilot CLI): GitHub Copilot has its own plugin system with a compatible structure. It discovers plugin.json in .claude-plugin/ — the same location harness-kit uses — and follows the same skills/NAME/SKILL.md path. Install directly from the repo:
copilot plugin install siracusa5/harness-kit
Manual — repo-wide instructions: Copy a plugin's SKILL.md to .github/copilot-instructions.md. Copilot picks it up automatically for all conversations in that repo.
Path-scoped instructions: Drop it in .github/instructions/<name>.instructions.md and add an applyTo glob in the frontmatter:
---
applyTo: "src/**"
---
[SKILL.md content here]
CLAUDE.md native support: VS Code Copilot reads CLAUDE.md natively when chat.useClaudeMdFile is enabled in settings. If you've configured harness-kit via CLAUDE.md, the conventions guide works in Copilot out of the box — zero changes required.
This convergence means a single CLAUDE.md can serve both Claude Code and Copilot simultaneously. You don't need to maintain separate instruction files.
Skills directories: Some VS Code Copilot configurations recognize .claude/skills/ alongside .github/skills/. Check the Copilot customization docs for current skill directory support in your version.
Example — installing the explain skill as a scoped Copilot instruction:
---
applyTo: "**"
---
[contents of explain/SKILL.md]
Save as .github/instructions/explain.instructions.md. The skill is now available in Copilot Chat for all files.
Cursor
Copy a plugin's SKILL.md to .cursor/rules/<name>.mdc (note the .mdc extension). Cursor's globs: frontmatter key maps directly to harness-kit's scope controls if you want to restrict a skill to specific paths:
---
globs: "src/**/*.ts"
---
[SKILL.md content here]
Windsurf
Copy the SKILL.md content into .windsurfrules, or paste it through Windsurf's project rules UI. No frontmatter needed — Windsurf applies rules project-wide.
MCP Servers
MCP has 100% cross-platform support — it's the only harness-kit feature that works identically everywhere. The wiring location varies by tool:
| Tool | MCP config file |
|---|---|
| Claude Code | .mcp.json |
| Copilot (VS Code) | .vscode/mcp.json |
| Cursor | .cursor/mcp.json |
Plugins that depend on MCP (like orient and capture-session) work in any of these tools as long as the server is wired up.
What You Lose
| Feature | Claude Code | Other Tools |
|---|---|---|
| Marketplace install/update | ✅ One command | ✅ Copilot CLI / ❌ Cursor, Windsurf |
| Hooks | ✅ Auto-triggered | ❌ Harness-specific |
| Auto-execution scripts | ✅ Bundled | ❌ Run manually |
| SKILL.md workflows | ✅ | ✅ |
| MCP server support | ✅ | ✅ (varies by tool) |