Agent Plugins

An Agent Plugin is an installable bundle of instructions and tools for your site's built-in AI assistant — packaged and versioned like any other piece of software, instead of pasted into a settings box. It's a different thing from a CMS plugin, which extends the content system itself: see How Plugins Work and The Plugin API for that side.

What it's for

Install one to give the assistant a skill it doesn't have out of the box. Higgsfield, below, is a real example already installed on this site: it lets the assistant generate an image and file it into your Media library, on request.

Higgsfield: image generation

Higgsfield connects your assistant to an outside image-generation service. Turned on, the assistant can ask it for an image, wait for the job to finish, and add the result to Media as a normal file — same table, same renditions as anything you upload yourself.

This connection covers images. Video generation is part of Higgsfield's own service but isn't wired into this plugin.

Turning it on

• Enable the plugin — the Agent Plugins screen in your admin, or just ask the assistant to turn Higgsfield on. It ships off by default, so this is a one-time step, and the assistant needs a restart to pick it up.
• Connect the account — Settings → External MCP, then sign in with your Higgsfield account in the browser window that opens. It's OAuth: there's no API key to find or paste anywhere.

Asking for one

Once it's connected, ask in plain language:

Generate an image of a red fox in a snowy pine forest at dawn with Higgsfield, and add it to Media.

The assistant starts the job, checks back until it's done — generation usually takes 10–20 seconds — and imports the finished image. This is that exact image, still in this site's Media library:

Generated with Higgsfield (z_image).

Which models are available depends on your own Higgsfield plan — if one is gated, the assistant tries another rather than stopping.

What's inside one

An Agent Plugin is just a directory: a manifest plus a couple of fixed subfolders, no build step. This is supabase, one of the plugins bundled with this site, exactly as it sits on disk:

supabase/
├── plugin.json
├── mcp.json
└── skills/
    └── supabase/
        ├── SKILL.md
        └── references/
            └── failure-modes.md

• plugin.json is the manifest — it names the plugin and the spec version it's written against.
• skills/<name>/SKILL.md is what the assistant reads for context: plain instructions, not code that runs.
• mcp.json points at an external MCP server when the plugin needs one — Supabase's connects over OAuth.

A manifest only needs two fields to be valid here:

{
  "$schema": "https://agent-plugins.org/schemas/1.0.0/plugin.schema.json",
  "name": "supabase"
}

Full format: Agent Plugins specification →

More on plugins

How plugins are scoped, permissioned, and installed in general lives on How Plugins Work. The code-level surface a plugin author writes against is on The Plugin API.