> Originally created by Sahaj Jain ([@jnsahaj](https://github.com/jnsahaj)) and continued here with permission.
Each coding agent — Claude Code, Codex, Gemini CLI, Copilot, Cursor, Windsurf, Pi, OpenCode — has its own plugin system, file layout, and frontmatter rules. **agent-plugin-sdk** lets you define a plugin **once** in TypeScript and compiles it to the **native installable artifacts** each harness expects. No runtime, no wrapper — the output is exactly the files those harnesses load on their own.
```ts
import { definePlugin, defineSkill } from "@jalco/ap-sdk";
export default definePlugin({
id: "git-helper",
description: "Helpers for reviewing and committing changes in a git repo.",
skills: [
defineSkill({
name: "diff-review",
description:
"Summarize and risk-flag uncommitted changes. Use when the user asks what changed.",
instructions:
"Run `git diff HEAD` and summarize the changes in 2-4 bullets.",
}),
],
});
```
```bash
ap-sdk build # → .aps-out/{claude,codex,gemini,copilot,cursor,windsurf,pi,opencode}/
ap-sdk install # → drops artifacts into your local harness dirs
```
## What you can define
| Field | What it becomes |
| --- | --- |
| [`instructions`](https://ap-sdk.dev/docs) | Always-on system or project guidance for every supported harness. |
| [`skills`](https://ap-sdk.dev/docs) | Reusable skill documents with descriptions and instructions. |
| [`commands`](https://ap-sdk.dev/docs) | Slash commands or prompt commands in harnesses that support them. |
| [`subagents`](https://ap-sdk.dev/docs) | Named specialist agents with their own prompts, tools, and model hints. |
| [`hooks`](https://ap-sdk.dev/docs) | Lifecycle hooks and scripts translated to each harness' event model. |
| [`mcpServers`](https://ap-sdk.dev/docs) | MCP server config emitted in native JSON/TOML/YAML formats. |
| [`tools`](https://ap-sdk.dev/docs) | Shared TypeScript tool implementations with per-harness glue. |
| [`files`](https://ap-sdk.dev/docs) | Companion files copied next to the generated native artifacts. |
See the [support matrix](https://ap-sdk.dev/docs/harnesses) for what each harness supports.
## Already have a plugin?
Point `ap-sdk port` at an existing Claude Code, Cursor, Codex, Gemini, Copilot, Windsurf, Pi, or OpenCode layout and it generates a portable `plugin.ts` that loads your existing files instead of inlining them.
```bash
npx ap-sdk port ./my-plugin
npx ap-sdk check ./plugin.ts
npx ap-sdk install owner/repo
```
Read the [porting guide](https://ap-sdk.dev/docs/porting), or install straight from GitHub with `ap-sdk install owner/repo`.
## Install
```bash
pnpm add -D @jalco/ap-sdk
```
[Docs](https://ap-sdk.dev/docs) · [Examples](https://github.com/jal-co/agent-plugin-sdk/tree/main/packages/agent-plugin-sdk/examples)
## License
[MIT](https://github.com/jal-co/agent-plugin-sdk/tree/HEAD/LICENSE) · Originally by [Sahaj Jain](https://github.com/jnsahaj), continued by [Justin Levine](https://github.com/jal-co).
