Check your plugin.json before you ship it

Questions people ask

Where does plugin.json go?

For a portable plugin, put plugin.json at the plugin root. Older Codex plugins use .codex-plugin/plugin.json, which OpenAI still supports as a fallback. This checker handles both.

What fields does a Codex plugin.json need?

name is the one that really matters, and it should be kebab-case. version and description are strongly recommended. OpenAI-specific stuff like interface, apps and hooks lives under extensions.com.openai.

Why does every path need to start with ./?

Paths are resolved from the plugin root. OpenAI's docs say to keep them relative and starting with ./. Absolute paths or anything with .. can point outside the package and break once it's installed.

Does this check my marketplace.json too?

Yes. If your JSON has a plugins array, it's treated as a marketplace and each entry is checked for a source, policy.installation, policy.authentication and category.

Is this the official validator?

No. It's a quick check we wrote based on OpenAI's published docs. It catches the common mistakes but it doesn't replace testing your plugin in Codex or the ChatGPT app.