How do I install the Plugin Authoring skill?

Run npx skillmds@latest add pleaseai/plugin-authoring in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Plugin Authoring safe to use?

This skill has not completed SkillMD's automated safety review yet. Capability flags: docs only. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Plugin Authoring?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Plugin Authoring free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Plugin Authoring?

pleaseai (@pleaseai) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Plugin Authoring by pleaseai — Agent Skill

Name: Plugin Authoring
Rating: 4.2 (5 reviews)
Author: pleaseai

Plugin Authoring

Author, scaffold, or edit a plugin once in Claude Code format, then generate the Codex, Antigravity, and Cursor manifests so one directory loads in all four runtimes. Use when creating/scaffolding a new plugin, editing a plugin or its manifest, wiring a marketplace entry, running the multi-format generator, or when the user mentions "plugin.json", ".claude-plugin", ".codex-plugin", ".cursor-plugin", "multi-format", "marketplace.json", "scaffold a plugin", or "Codex/Cursor/Antigravity plugin".

pleaseai 04e4fa5 4 files · 14.8 KB Updated Sep 10, 2026

File contents

Plugin Authoring — Multi-Runtime

This marketplace ships the same plugin directory across four runtimes. You author once in Claude Code format (the source of truth) and generate the rest. Never hand-write the Codex, Antigravity, or Cursor manifests.

.claude-plugin/plugin.json                          ← author here, source of truth
        │  bun scripts/cli.ts multi-format
        ▼
.codex-plugin/plugin.json + .mcp.json               ← generated
plugin.json (root) + mcp_config.json + hooks.json   ← generated (Antigravity)
.cursor-plugin/plugin.json                           ← generated
.agents/plugins/marketplace.json                     ← generated (Codex marketplace)
.cursor-plugin/marketplace.json                      ← generated (Cursor marketplace)

Workflow

Scaffold / edit the plugin in Claude Code format. Components go at the plugin root, never inside .claude-plugin/:
```
plugins/<name>/
├── .claude-plugin/plugin.json   # manifest only (source of truth)
├── commands/  agents/  skills/  # at root, auto-discovered
└── hooks/hooks.json             # at root
```
Author the manifest from references/plugin-json-spec.md — start with valid defaults, no [TODO: ...] placeholders. Prefer skills over SessionStart hooks (they load only when relevant). Full quality checklist: references/best-practices.md.
Register in .claude-plugin/marketplace.json (source: "./plugins/<name>"). Claude-only fields like relevance live only here. For a new plugin, wire the companion files (release-please, README) too — see references/multi-runtime-manifests.md.
Generate the other runtimes:
```
bun scripts/cli.ts multi-format
```
The generator is bundled in this plugin (scripts/run.ts + scripts/multi-format.ts). Details, the per-runtime mapping table, and the $schema each manifest carries: references/multi-runtime-manifests.md.
Scope the diff — the generator rewrites all local plugins; git restore any unrelated churn so the commit stays atomic.
Validate — claude plugin validate plugins/<name>; deeper audit via the validating-plugins skill.

Manifest location

Every local plugin's Claude source is .claude-plugin/plugin.json; the root plugin.json is the generated Antigravity manifest. Edit the .claude-plugin/ file — never the root one — then re-run multi-format.

References (load on demand)

references/plugin-json-spec.md — manifest + marketplace field guide with canonical samples.
references/multi-runtime-manifests.md — per-runtime mapping, the generator, diff scoping.
references/best-practices.md — quality checklist, pitfalls, testing.

validating-plugins — audit a plugin's manifest and structure before release.
migrating-gemini-extensions — port a Gemini CLI extension to Claude Code.
Cross-runtime creation skills: claude-code-plugin-builder (Claude Code component deep-dive), plugin-creator (Codex-native), create-plugin-scaffold (Cursor-native).

What NOT to do

❌ Hand-edit .codex-plugin/, .cursor-plugin/, the generated root Antigravity plugin.json, or the Codex/Cursor marketplace.json — re-run multi-format.
❌ Put relevance (or other Claude-only fields) in the Codex/Cursor marketplaces.
❌ Nest commands/ / agents/ / skills/ inside .claude-plugin/ — they won't load.

---name: plugin-authoringdescription: Author, scaffold, or edit a plugin once in Claude Code format, then generate the Codex, Antigravity, and Cursor manifests so one directory loads in all four runtimes. Use when creating/scaffolding a new plugin, editing a plugin or its manifest, wiring a marketplace entry, running the multi-format generator, or when the user mentions "plugin.json", ".claude-plugin", ".codex-plugin", ".cursor-plugin", "multi-format", "marketplace.json", "scaffold a plugin", or "Codex/Cursor/Antigravity plugin".---# Plugin Authoring — Multi-RuntimeThis marketplace ships the **same plugin directory across four runtimes**. You author **once** inClaude Code format (the source of truth) and **generate** the rest. Never hand-write the Codex,Antigravity, or Cursor manifests.```.claude-plugin/plugin.json ← author here, source of truth │ bun scripts/cli.ts multi-format ▼.codex-plugin/plugin.json + .mcp.json ← generatedplugin.json (root) + mcp_config.json + hooks.json ← generated (Antigravity).cursor-plugin/plugin.json ← generated.agents/plugins/marketplace.json ← generated (Codex marketplace).cursor-plugin/marketplace.json ← generated (Cursor marketplace)```## Workflow1. **Scaffold / edit** the plugin in Claude Code format. Components go at the plugin **root**, never inside `.claude-plugin/`: ``` plugins/<name>/ ├── .claude-plugin/plugin.json # manifest only (source of truth) ├── commands/ agents/ skills/ # at root, auto-discovered └── hooks/hooks.json # at root ``` Author the manifest from `references/plugin-json-spec.md` — start with valid defaults, no `[TODO: ...]` placeholders. Prefer **skills** over SessionStart hooks (they load only when relevant). Full quality checklist: `references/best-practices.md`.2. **Register** in `.claude-plugin/marketplace.json` (`source: "./plugins/<name>"`). Claude-only fields like `relevance` live **only** here. For a new plugin, wire the companion files (release-please, README) too — see `references/multi-runtime-manifests.md`.3. **Generate** the other runtimes: ```bash bun scripts/cli.ts multi-format ``` The generator is bundled in this plugin (`scripts/run.ts` + `scripts/multi-format.ts`). Details, the per-runtime mapping table, and the `$schema` each manifest carries: `references/multi-runtime-manifests.md`.4. **Scope the diff** — the generator rewrites *all* local plugins; `git restore` any unrelated churn so the commit stays atomic.5. **Validate** — `claude plugin validate plugins/<name>`; deeper audit via the `validating-plugins` skill.## Manifest locationEvery local plugin's Claude source is `.claude-plugin/plugin.json`; the root `plugin.json` is the**generated** Antigravity manifest. Edit the `.claude-plugin/` file — never the root one — thenre-run `multi-format`.## References (load on demand)- `references/plugin-json-spec.md` — manifest + marketplace field guide with canonical samples.- `references/multi-runtime-manifests.md` — per-runtime mapping, the generator, diff scoping.- `references/best-practices.md` — quality checklist, pitfalls, testing.## Related- `validating-plugins` — audit a plugin's manifest and structure before release.- `migrating-gemini-extensions` — port a Gemini CLI extension to Claude Code.- Cross-runtime creation skills: `claude-code-plugin-builder` (Claude Code component deep-dive), `plugin-creator` (Codex-native), `create-plugin-scaffold` (Cursor-native).## What NOT to do- ❌ Hand-edit `.codex-plugin/`, `.cursor-plugin/`, the generated root Antigravity `plugin.json`, or the Codex/Cursor `marketplace.json` — re-run `multi-format`.- ❌ Put `relevance` (or other Claude-only fields) in the Codex/Cursor marketplaces.- ❌ Nest `commands/` / `agents/` / `skills/` inside `.claude-plugin/` — they won't load.

Frequently asked questions