# Read-only Database MCP

Minimal TeamSpeak/TypeScript setup that exposes a read-only database Model Context Protocol server and a small UI for managing DB configs, toggling light/dark mode, and viewing usage history.

## Prerequisites

- Node 18+
- A PostgreSQL or MySQL/MariaDB database user with read-only permissions

## Install

```bash
npm install
```

## Run the UI + API

Serves the config/history API and the minimalist UI at `http://localhost:4000`.

```bash
npm run dev
```

## Run the MCP server

The MCP server reads the same saved configs from `data/state.json` and only exposes read-only tools.

```bash
npm run mcp
```

Tools exposed (over stdio):
- `list_tables` — input `{ db: "<configName>" }`
- `preview_table` — input `{ db: "<configName>", table: "table_name", limit?: number }`
- `run_select` — input `{ db: "<configName>", sql: "SELECT ..." }` (rejects non-SELECT)

Use these tool names when connecting your model/agent to the MCP server.

## How to use

1) Start `npm run dev` and open the UI. Enter DB connection details and click **Save config**. Set SSL mode to `disable`, `require`, or `no-verify` (self-signed).  
   - For MySQL/MariaDB TCP/IP, pick type “MySQL / MariaDB”.  
2) Select the saved config in “Use config” to list tables, preview a table, or run a SELECT.  
3) Each successful MCP/HTTP call records a history entry (DB name, tables touched, timestamp).  
4) In your agent, connect to the MCP server via stdio and call the tools using the saved `db` name; you only need to pass the friendly name, not the credentials.

## Notes

- Configs and history live in `data/state.json`. Delete that file to reset.  
- The server enforces read-only mode with `SET SESSION CHARACTERISTICS AS TRANSACTION READ ONLY` and rejects non-SELECT queries.  
- If your MCP SDK exports different helper names, adjust `src/mcp-server.ts` registration to match your SDK version.  
- Extend `src/db.ts` to add other engines (MySQL, SQLite) while keeping read-only guards.