supabase

Supabase Agent Plugin

Investigate Supabase-backed apps: schema, data access, RLS, and auth — via Supabase's official PostgREST MCP server.

An Agent Plugin (spec 1.0.0).

What is this?

A plugin that pairs Supabase's official @supabase/mcp-server-postgrest with skills for schema inspection, RLS review, auth debugging, and end-to-end investigation of a Supabase-backed app.

Why would I install it?

• First-party upstream — Supabase's own MCP server (repo supabase/mcp, Apache-2.0).
• Workflow value, not tool listing — the skills teach investigation order (schema → access → RLS → auth), not just what the tools do.
• Project-scoped, read-first — skills default to GET; writes require explicit intent.

What MCP/upstream does it use?

• Server: supabase — stdio, npx -y @supabase/mcp-server-postgrest@0.1.1 --apiUrl <your-project-url> --schema public (pinned, first-party).
• Skills: inspect-schema, review-rls, debug-auth, investigate-supabase-app.

Does it need authentication?

Project configuration, not plugin secrets. The --apiUrl in the config is a placeholder (https://your-project-ref.supabase.co/rest/v1) that must be replaced with your project's URL — this is per-project configuration, not a credential. The optional --apiKey (anon key) is supplied at the client level; never commit a key. Agent Plugins v1 has no portable secret mechanism, so auth stays client/user managed.

Is it read-only?

Skills default to read-only (GET requests via postgrestRequest). The official server can do CRUD (POST/PATCH/DELETE); the plugin's skills never mutate during investigation and require explicit user intent for writes. Read-only enforcement is the project's RLS + the anon role.

What clients were actually tested?

stdio MCP transport. The pinned server was runtime-verified in this release cycle:

handshake  OK (supabase/postgrest 0.1.1)
tools/list postgrestRequest, sqlToRest

Status: HANDSHAKE_VERIFIED / TOOLS_VERIFIED. A real project call requires a Supabase project URL (client-configurable); the placeholder URL is not callable. Verify against your project in your client.

Requirements

• Node.js 18+ with npx.
• A Supabase project (or any PostgREST server) URL.
• Network access to the project and the npm registry.

Installation

Copy the plugin's runtime files (plugin.json, mcp.json, skills/, README.md, LICENSE) into your Agent Plugins client's plugin folder, or use your client's plugin install flow. Do not copy the authoring sources (plugin.yml, skills-src/, docs/) — see the collection README for the full boundary. No build step is required.

Configuration

Replace the placeholder project URL with your own:

{
  "mcpServers": {
    "supabase": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@supabase/mcp-server-postgrest@0.1.1",
        "--apiUrl",
        "https://your-project-ref.supabase.co/rest/v1",
        "--schema",
        "public"
      ]
    }
  }
}

• --apiUrl: your project's PostgREST endpoint (required, project-specific).
• --apiKey: optional; supply at the client level, never commit it.
• --schema: the schema to serve (default public).

Examples

1. "Show me the schema of my Supabase project" → inspect-schema.
2. "Audit whether our tables are RLS-protected" → review-rls.
3. "Users can't sign in — help debug" → debug-auth.
4. "Why is this feature returning no data?" → investigate-supabase-app.

Upstream MCP

Server	Version	License	Source
Supabase PostgREST MCP	@supabase/mcp-server-postgrest@0.1.1 (pinned)	Apache-2.0	supabase/mcp

Agent Plugins version

1.0.0 (Working Draft) — https://agent-plugins.org/specification

Runtime requirements

Node.js 18+, npx, network access, a Supabase/PostgREST project URL.

Security / default behavior

• Read-first skills; no data mutation during investigation.
• No API keys in the plugin; keys are client-level.
• Placeholder --apiUrl must be replaced by the user (per-project config).
• Do not print tokens, keys, or sensitive row data.

Known limitations

• The --apiUrl is project-specific and cannot be shipped pre-configured.
• RLS review needs SQL access (dashboard/SQL editor) for pg_policies — the MCP alone cannot read them.
• Writes require explicit user intent; the server itself is not read-only.

License

MIT. See LICENSE. Upstream @supabase/mcp-server-postgrest is Apache-2.0 (Supabase); HiAI is not affiliated with or endorsed by Supabase.

CHANGELOG

See CHANGELOG.md.