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 harnessprotocol/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.

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]

Codex

Copy a plugin's SKILL.md into your AGENTS.md file, or place it in a project-level AGENTS.md at the repo root. Codex reads AGENTS.md as its persistent instruction context — the same role CLAUDE.md plays for Claude Code.

cat plugins/research/skills/research/SKILL.md >> AGENTS.md

MCP servers: Codex supports MCP via the --mcp flag. Pass your .mcp.json at startup:

codex --mcp .mcp.json

Plugins that depend on MCP (orient, capture, membrain) work with Codex once the server is wired up this way.

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:

Plugins that depend on MCP (like orient and capture) work in any of these tools as long as the server is wired up.

What You Lose