Self-Hosted Supabase MCP Server

Overview

This project provides a Model Context Protocol (MCP) server designed specifically for interacting with self-hosted Supabase instances. It bridges the gap between MCP clients (like IDE extensions) and your local or privately hosted Supabase projects, enabling database introspection, management, and interaction directly from your development environment.

This server was built from scratch, drawing lessons from adapting the official Supabase cloud MCP server, to provide a minimal, focused implementation tailored for the self-hosted use case.

Purpose

The primary goal of this server is to enable developers using self-hosted Supabase installations to leverage MCP-based tools for tasks such as:

Querying database schemas and data.
Managing database migrations.
Inspecting database statistics and connections.
Managing authentication users.
Interacting with Supabase Storage.
Generating type definitions.

It avoids the complexities of the official cloud server related to multi-project management and cloud-specific APIs, offering a streamlined experience for single-project, self-hosted environments.

Features (Implemented Tools)

The server exposes the following tools to MCP clients:

Schema & Migrations
- list_tables: Lists tables in the database schemas.
- list_extensions: Lists installed PostgreSQL extensions.
- list_migrations: Lists applied Supabase migrations.
- apply_migration: Applies a SQL migration script.
Database Operations & Stats
- execute_sql: Executes an arbitrary SQL query (via RPC or direct connection).
- get_database_connections: Shows active database connections (pg_stat_activity).
- get_database_stats: Retrieves database statistics (pg_stat_*).
Project Configuration & Keys
- get_project_url: Returns the configured Supabase URL.
- get_anon_key: Returns the configured Supabase anon key.
- get_service_key: Returns the configured Supabase service role key (if provided).
- verify_jwt_secret: Checks if the JWT secret is configured and returns a preview.
Development & Extension Tools
- generate_typescript_types: Generates TypeScript types from the database schema.
- rebuild_hooks: Attempts to restart the pg_net worker (if used).
Auth User Management
- list_auth_users: Lists users from auth.users.
- get_auth_user: Retrieves details for a specific user.
- create_auth_user: Creates a new user (Requires direct DB access, insecure password handling).
- delete_auth_user: Deletes a user (Requires direct DB access).
- update_auth_user: Updates user details (Requires direct DB access, insecure password handling).
Storage Insights
- list_storage_buckets: Lists all storage buckets.
- list_storage_objects: Lists objects within a specific bucket.
Realtime Inspection
- list_realtime_publications: Lists PostgreSQL publications (often supabase_realtime).

(Note: get_logs was initially planned but skipped due to implementation complexities in a self-hosted environment).

Setup and Installation

Installing via Smithery

To install Self-Hosted Supabase MCP Server for Claude Desktop automatically via Smithery:

npx -y @smithery/cli install @HenkDz/selfhosted-supabase-mcp --client claude

Prerequisites

Node.js (Version 18.x or later recommended)
npm (usually included with Node.js)
Access to your self-hosted Supabase instance (URL, keys, potentially direct DB connection string).

Steps

Clone the repository:

git clone <repository-url>
cd self-hosted-supabase-mcp

Install dependencies:
```
npm install
```
Build the project:
```
npm run build
```
This compiles the TypeScript code to JavaScript in the dist directory.

Configuration

The server requires configuration details for your Supabase instance. These can be provided via command-line arguments or environment variables. CLI arguments take precedence.

Required:

--url <url> or SUPABASE_URL=<url>: The main HTTP URL of your Supabase project (e.g., http://localhost:8000).
--anon-key <key> or SUPABASE_ANON_KEY=<key>: Your Supabase project's anonymous key.

Optional (but Recommended/Required for certain tools):

--service-key <key> or SUPABASE_SERVICE_ROLE_KEY=<key>: Your Supabase project's service role key. Needed for operations requiring elevated privileges, like attempting to automatically create the execute_sql helper function if it doesn't exist.
--db-url <url> or DATABASE_URL=<url>: The direct PostgreSQL connection string for your Supabase database (e.g., postgresql://postgres:password@localhost:5432/postgres). Required for tools needing direct database access or transactions (apply_migration, Auth tools, Storage tools, querying pg_catalog, etc.).
--jwt-secret <secret> or SUPABASE_AUTH_JWT_SECRET=<secret>: Your Supabase project's JWT secret. Needed for tools like verify_jwt_secret.
--tools-config <path>: Path to a JSON file specifying which tools to enable (whitelist). If omitted, all tools defined in the server are enabled. The file should have the format {"enabledTools": ["tool_name_1", "tool_name_2"]}.

Important Notes:

execute_sql Helper Function: Many tools rely on a public.execute_sql function within your Supabase database for secure and efficient SQL execution via RPC. The server attempts to check for this function on startup. If it's missing and a service-key (or SUPABASE_SERVICE_ROLE_KEY) and db-url (or DATABASE_URL) are provided, it will attempt to create the function and grant necessary permissions. If creation fails or keys aren't provided, tools relying solely on RPC may fail.
Direct Database Access: Tools interacting directly with privileged schemas (auth, storage) or system catalogs (pg_catalog) generally require the DATABASE_URL to be configured for a direct pg connection.

Usage

Run the server using Node.js, providing the necessary configuration:

# Using CLI arguments (example)
node dist/index.js --url http://localhost:8000 --anon-key <your-anon-key> --db-url postgresql://postgres:password@localhost:5432/postgres [--service-key <your-service-key>]

# Example with tool whitelisting via config file
node dist/index.js --url http://localhost:8000 --anon-key <your-anon-key> --tools-config ./mcp-tools.json

# Or configure using environment variables and run:
# export SUPABASE_URL=http://localhost:8000
# export SUPABASE_ANON_KEY=<your-anon-key>
# export DATABASE_URL=postgresql://postgres:password@localhost:5432/postgres
# export SUPABASE_SERVICE_ROLE_KEY=<your-service-key>
# The --tools-config option MUST be passed as a CLI argument if used
node dist/index.js

# Using npm start script (if configured in package.json to pass args/read env)
npm start -- --url ... --anon-key ...

The server communicates via standard input/output (stdio) and is designed to be invoked by an MCP client application (e.g., an IDE extension like Cursor). The client will connect to the server's stdio stream to list and call the available tools.

Client Configuration Examples

Below are examples of how to configure popular MCP clients to use this self-hosted server.

Important:

Replace placeholders like <your-supabase-url>, <your-anon-key>, <your-db-url>, <path-to-dist/index.js> etc., with your actual values.
Ensure the path to the compiled server file (dist/index.js) is correct for your system.
Be cautious about storing sensitive keys directly in configuration files, especially if committed to version control. Consider using environment variables or more secure methods where supported by the client.

Cursor

Create or open the file .cursor/mcp.json in your project root.

Add the following configuration:

{
  "mcpServers": {
    "selfhosted-supabase": { 
      "command": "node",
      "args": [
        "<path-to-dist/index.js>", // e.g., "F:/Projects/mcp-servers/self-hosted-supabase-mcp/dist/index.js"
        "--url",
        "<your-supabase-url>", // e.g., "http://localhost:8000"
        "--anon-key",
        "<your-anon-key>",
        // Optional - Add these if needed by the tools you use
        "--service-key",
        "<your-service-key>",
        "--db-url",
        "<your-db-url>", // e.g., "postgresql://postgres:password@host:port/postgres"
        "--jwt-secret",
        "<your-jwt-secret>",
        // Optional - Whitelist specific tools
        "--tools-config",
        "<path-to-your-mcp-tools.json>" // e.g., "./mcp-tools.json"
      ]
    }
  }
}

Visual Studio Code (Copilot)

VS Code Copilot allows using environment variables populated via prompted inputs, which is more secure for keys.

Create or open the file .vscode/mcp.json in your project root.