plugin-creator
Create and scaffold plugin directories for Codex with a required `.codex-plugin/plugin.json`, optional plugin folders/files, and baseline placeholders you can edit before publishing or testing. Use when Codex needs to create a new local plugin, add optional plugin structure, or generate or update repo-root `.agents/plugins/marketplace.json` entries for plugin ordering and availability metadata.
Best use case
plugin-creator is best used when you need a repeatable AI agent workflow instead of a one-off prompt.
Create and scaffold plugin directories for Codex with a required `.codex-plugin/plugin.json`, optional plugin folders/files, and baseline placeholders you can edit before publishing or testing. Use when Codex needs to create a new local plugin, add optional plugin structure, or generate or update repo-root `.agents/plugins/marketplace.json` entries for plugin ordering and availability metadata.
Teams using plugin-creator should expect a more consistent output, faster repeated execution, less prompt rewriting.
When to use this skill
- You want a reusable workflow that can be run more than once with consistent structure.
When not to use this skill
- You only need a quick one-off answer and do not need a reusable workflow.
- You cannot install or maintain the underlying files, dependencies, or repository context.
Installation
Claude Code / Cursor / Codex
Manual Installation
- Download SKILL.md from GitHub
- Place it in
.claude/skills/plugin-creator/SKILL.mdinside your project - Restart your AI agent — it will auto-discover the skill
How plugin-creator Compares
| Feature / Agent | plugin-creator | Standard Approach |
|---|---|---|
| Platform Support | Not specified | Limited / Varies |
| Context Awareness | High | Baseline |
| Installation Complexity | Unknown | N/A |
Frequently Asked Questions
What does this skill do?
Create and scaffold plugin directories for Codex with a required `.codex-plugin/plugin.json`, optional plugin folders/files, and baseline placeholders you can edit before publishing or testing. Use when Codex needs to create a new local plugin, add optional plugin structure, or generate or update repo-root `.agents/plugins/marketplace.json` entries for plugin ordering and availability metadata.
Where can I find the source code?
You can find the source code on GitHub using the link provided at the top of the page.
SKILL.md Source
# Plugin Creator
## Quick Start
1. Run the scaffold script:
```bash
# Plugin names are normalized to lower-case hyphen-case and must be <= 64 chars.
# The generated folder and plugin.json name are always the same.
# Run from repo root (or replace .agents/... with the absolute path to this SKILL).
# By default creates in <repo_root>/plugins/<plugin-name>.
python3 .agents/skills/plugin-creator/scripts/create_basic_plugin.py <plugin-name>
```
2. Open `<plugin-path>/.codex-plugin/plugin.json` and replace `[TODO: ...]` placeholders.
3. Generate or update the repo marketplace entry when the plugin should appear in Codex UI ordering:
```bash
# marketplace.json always lives at <repo-root>/.agents/plugins/marketplace.json
python3 .agents/skills/plugin-creator/scripts/create_basic_plugin.py my-plugin --with-marketplace
```
4. Generate/adjust optional companion folders as needed:
```bash
python3 .agents/skills/plugin-creator/scripts/create_basic_plugin.py my-plugin --path <parent-plugin-directory> \
--with-skills --with-hooks --with-scripts --with-assets --with-mcp --with-apps --with-marketplace
```
`<parent-plugin-directory>` is the directory where the plugin folder `<plugin-name>` will be created (for example `~/code/plugins`).
## What this skill creates
- Creates plugin root at `/<parent-plugin-directory>/<plugin-name>/`.
- Always creates `/<parent-plugin-directory>/<plugin-name>/.codex-plugin/plugin.json`.
- Fills the manifest with the full schema shape, placeholder values, and the complete `interface` section.
- Creates or updates `<repo-root>/.agents/plugins/marketplace.json` when `--with-marketplace` is set.
- If the marketplace file does not exist yet, seed top-level `name` plus `interface.displayName` placeholders before adding the first plugin entry.
- `<plugin-name>` is normalized using skill-creator naming rules:
- `My Plugin` → `my-plugin`
- `My--Plugin` → `my-plugin`
- underscores, spaces, and punctuation are converted to `-`
- result is lower-case hyphen-delimited with consecutive hyphens collapsed
- Supports optional creation of:
- `skills/`
- `hooks/`
- `scripts/`
- `assets/`
- `.mcp.json`
- `.app.json`
## Marketplace workflow
- `marketplace.json` always lives at `<repo-root>/.agents/plugins/marketplace.json`.
- Marketplace root metadata supports top-level `name` plus optional `interface.displayName`.
- Treat plugin order in `plugins[]` as render order in Codex. Append new entries unless a user explicitly asks to reorder the list.
- `displayName` belongs inside the marketplace `interface` object, not individual `plugins[]` entries.
- Each generated marketplace entry must include all of:
- `policy.installation`
- `policy.authentication`
- `category`
- Default new entries to:
- `policy.installation: "AVAILABLE"`
- `policy.authentication: "ON_INSTALL"`
- Override defaults only when the user explicitly specifies another allowed value.
- Allowed `policy.installation` values:
- `NOT_AVAILABLE`
- `AVAILABLE`
- `INSTALLED_BY_DEFAULT`
- Allowed `policy.authentication` values:
- `ON_INSTALL`
- `ON_USE`
- Treat `policy.products` as an override. Omit it unless the user explicitly requests product gating.
- The generated plugin entry shape is:
```json
{
"name": "plugin-name",
"source": {
"source": "local",
"path": "./plugins/plugin-name"
},
"policy": {
"installation": "AVAILABLE",
"authentication": "ON_INSTALL"
},
"category": "Productivity"
}
```
- Use `--force` only when intentionally replacing an existing marketplace entry for the same plugin name.
- If `<repo-root>/.agents/plugins/marketplace.json` does not exist yet, create it with top-level `"name"`, an `"interface"` object containing `"displayName"`, and a `plugins` array, then add the new entry.
- For a brand-new marketplace file, the root object should look like:
```json
{
"name": "[TODO: marketplace-name]",
"interface": {
"displayName": "[TODO: Marketplace Display Name]"
},
"plugins": [
{
"name": "plugin-name",
"source": {
"source": "local",
"path": "./plugins/plugin-name"
},
"policy": {
"installation": "AVAILABLE",
"authentication": "ON_INSTALL"
},
"category": "Productivity"
}
]
}
```
## Required behavior
- Outer folder name and `plugin.json` `"name"` are always the same normalized plugin name.
- Do not remove required structure; keep `.codex-plugin/plugin.json` present.
- Keep manifest values as placeholders until a human or follow-up step explicitly fills them.
- If creating files inside an existing plugin path, use `--force` only when overwrite is intentional.
- Preserve any existing marketplace `interface.displayName`.
- When generating marketplace entries, always write `policy.installation`, `policy.authentication`, and `category` even if their values are defaults.
- Add `policy.products` only when the user explicitly asks for that override.
- Keep marketplace `source.path` relative to repo root as `./plugins/<plugin-name>`.
## Reference to exact spec sample
For the exact canonical sample JSON for both plugin manifests and marketplace entries, use:
- `references/plugin-json-spec.md`
## Validation
After editing `SKILL.md`, run:
```bash
python3 <path-to-skill-creator>/scripts/quick_validate.py .agents/skills/plugin-creator
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