> ## Documentation Index
> Fetch the complete documentation index at: https://docs.civic.com/llms.txt
> Use this file to discover all available pages before exploring further.

# MySQL

> MySQL database — execute SQL queries including SELECT and optional DML operations

## Overview

MySQL is a widely used open-source relational database. Connect it to Civic to let your AI agent run SQL queries against your MySQL database, with configurable support for read-only or read-write operations.

<Card title="Add to Civic" icon="plus" href="https://app.civic.com">
  Connect MySQL at app.civic.com
</Card>

## Available Tools (1)

| Tool          | Description                                                                                                                                           |
| ------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------- |
| `mysql_query` | Execute SQL queries against the MySQL database. SELECT is always enabled; INSERT, UPDATE, DELETE, and DDL are enabled based on security configuration |

***

## Guardrails

In addition to the [14 universal guardrails](/civic/concepts/guardrails), this server has **16 server-specific guardrails** across 2 operations.

| Guardrail                       | Operation       | Timing   | Description                                                                    |
| ------------------------------- | --------------- | -------- | ------------------------------------------------------------------------------ |
| Block Dynamic SQL Construction  | `mysql_query`   | Request  | Prevents queries using CONCAT, CHAR functions, hex literals, DECODE, UNHEX     |
| Block Function Execution        | `mysql_query`   | Request  | Prevents execution of stored procedures and functions with side effects        |
| Block Query Stacking            | `mysql_query`   | Request  | Prevents multiple queries in a single request by blocking semicolons           |
| Block SQL Comments              | `mysql_query`   | Request  | Prevents queries containing SQL comments (--, /\* \*/, or #)                   |
| Block System Tables Access      | `mysql_query`   | Request  | Prevents access to MySQL system catalogs (mysql.\*, information\_schema)       |
| Block Write Operations          | `mysql_query`   | Request  | Prevents all data modification (INSERT, UPDATE, DELETE, etc.) and DDL commands |
| Enforce Basic SQL Character Set | `mysql_query`   | Request  | Restricts queries to alphanumeric plus basic SQL characters                    |
| Enforce Custom Character Set    | `mysql_query`   | Request  | Restricts queries to a user-defined character set                              |
| Limit JOIN Complexity           | `mysql_query`   | Request  | Limits the number of JOINs allowed in a query                                  |
| Protect Sensitive Columns       | `mysql_query`   | Request  | Blocks queries that reference specified column names                           |
| Protect Tables (Anti-Aliasing)  | `mysql_query`   | Request  | Blocks access to specified tables regardless of aliasing or obfuscation        |
| Query Length Limit              | `mysql_query`   | Request  | Limits SQL query length to prevent resource exhaustion                         |
| Restrict SELECT \* Usage        | `mysql_query`   | Request  | Controls use of SELECT \* wildcards                                            |
| Result Row Limit                | `mysql_query`   | Response | Limits the number of rows returned                                             |
| Block Table Schema Access       | `read_resource` | Request  | Prevents access to schema details of specified tables                          |
| Filter Table Listings           | `read_resource` | Response | Filters specified tables from table listings                                   |

<Tip>
  Configure guardrails via the Civic UI or ask the Configurator Agent: "Add guardrails to my MySQL server."
</Tip>