MySQL Connector

The MySQL connector enables AxonFlow agents to execute SQL queries and commands against MySQL and MariaDB databases with connection pooling, prepared statements, and policy enforcement.

Overview

Property	Value
Type	mysql
Edition	Community
Auth Methods	DSN, Username/Password
Capabilities	query, execute, transactions, prepared_statements, connection_pooling, last_insert_id

Use Cases

• Execute SQL queries for RAG context retrieval
• Store and retrieve application data with governance
• Access legacy MySQL databases in agent workflows
• Audit logging and compliance data management

Configuration

Environment Variables

# Option 1: Full DSN
MCP_mysql_CONNECTION_URL="user:password@tcp(host:3306)/database?parseTime=true"

# Option 2: Build from components
MCP_mysql_HOST="localhost"
MCP_mysql_PORT="3306"
MCP_mysql_DATABASE="mydb"
MCP_mysql_USER="myuser"
MCP_mysql_PASSWORD="mypassword"

# Optional - Connection Pool
MCP_mysql_MAX_OPEN_CONNS="25"
MCP_mysql_MAX_IDLE_CONNS="5"
MCP_mysql_CONN_MAX_LIFETIME="5m"
MCP_mysql_CONN_MAX_IDLE_TIME="5m"

# Optional - TLS
MCP_mysql_TLS="true"  # or "skip-verify", "preferred"

# Optional - Tenant isolation
MCP_mysql_TENANT_ID="*"

DSN Format

[user]:[password]@tcp([host]:[port])/[database]?[parameters]

Common Parameters:

• parseTime=true - Parse TIME/DATE/DATETIME to Go time.Time (recommended)
• loc=UTC - Timezone for parsed times
• charset=utf8mb4 - Character set (recommended for full UTF-8)
• timeout=10s - Connection timeout
• readTimeout=30s - Read timeout
• writeTimeout=30s - Write timeout
• tls=true - Enable TLS

Connector Config (Customer Portal)

{
  "name": "app-mysql",
  "type": "mysql",
  "options": {
    "host": "mysql.example.com",
    "port": 3306,
    "database": "appdb",
    "tls": "true",
    "max_open_conns": 25,
    "max_idle_conns": 5,
    "conn_max_lifetime": "5m"
  },
  "credentials": {
    "username": "app_user",
    "password": "secure_password"
  }
}

Operations

Query Operations

Execute SELECT statements with named or positional parameters:

# Using named parameters (:name)
curl -X POST https://your-axonflow.com/mcp/resources/query \
  -H "Content-Type: application/json" \
  -d '{
    "connector": "app-mysql",
    "statement": "SELECT id, name, email FROM users WHERE status = :status AND created_at > :date",
    "parameters": {
      "status": "active",
      "date": "2025-01-01"
    }
  }'

# Using positional parameters (?)
curl -X POST https://your-axonflow.com/mcp/resources/query \
  -d '{
    "connector": "app-mysql",
    "statement": "SELECT * FROM products WHERE category = ? AND price < ?",
    "parameters": {
      "0": "electronics",
      "1": 500.00
    }
  }'

Response:

{
  "success": true,
  "rows": [
    {"id": 1, "name": "Alice", "email": "[email protected]"},
    {"id": 2, "name": "Bob", "email": "[email protected]"}
  ],
  "row_count": 2,
  "duration_ms": 3.8,
  "connector": "app-mysql"
}

Execute Operations

Run INSERT, UPDATE, DELETE statements:

# INSERT (returns last_insert_id)
curl -X POST https://your-axonflow.com/mcp/tools/execute \
  -d '{
    "connector": "app-mysql",
    "action": "insert",
    "statement": "INSERT INTO users (name, email, created_at) VALUES (:name, :email, NOW())",
    "parameters": {
      "name": "Charlie",
      "email": "[email protected]"
    }
  }'

Response:

{
  "success": true,
  "rows_affected": 1,
  "duration_ms": 2.1,
  "message": "insert executed successfully (last_insert_id=42)",
  "connector": "app-mysql"
}

Named vs Positional Parameters

The MySQL connector supports both parameter styles:

Named Parameters (:name)

{
  "statement": "SELECT * FROM users WHERE name = :name AND status = :status",
  "parameters": {
    "name": "Alice",
    "status": "active"
  }
}

Positional Parameters (?)

{
  "statement": "SELECT * FROM users WHERE name = ? AND status = ?",
  "parameters": {
    "0": "Alice",
    "1": "active"
  }
}

Named parameters are converted to ? placeholders internally for MySQL.

Connection Pooling

Setting	Default	Description
max_open_conns	25	Maximum open connections
max_idle_conns	5	Maximum idle connections
conn_max_lifetime	5m	Maximum connection lifetime
conn_max_idle_time	5m	Maximum idle time before closing

Health Check

curl https://your-axonflow.com/mcp/connectors/app-mysql/health

Response:

{
  "healthy": true,
  "latency_ms": 1.5,
  "details": {
    "open_connections": "5",
    "in_use": "2",
    "idle": "3",
    "wait_count": "0",
    "mysql_version": "8.0.35"
  },
  "timestamp": "2025-12-08T10:30:00Z"
}

Data Type Handling

The connector automatically converts MySQL types to appropriate Go/JSON types:

MySQL Type	JSON Type
TINYINT, SMALLINT, INT, BIGINT	number
FLOAT, DOUBLE, DECIMAL	number (DECIMAL as string for precision)
VARCHAR, CHAR, TEXT	string
DATE, DATETIME, TIMESTAMP	string (ISO 8601)
JSON	object/array
BLOB, BINARY	base64 string
ENUM, SET	string
BOOLEAN	boolean

Best Practices

Security

1. Use TLS - Set tls=true for encrypted connections
2. Least privilege - Create users with minimal required permissions
3. Named parameters - Prevents SQL injection
4. Multi-statements disabled - Default setting blocks dangerous SQL

Performance

1. Index your queries - Use EXPLAIN to verify index usage
2. Connection pooling - Configure based on workload
3. Query timeouts - Set readTimeout/writeTimeout appropriately
4. Use LIMIT - Always limit result sets

Example User Setup

-- Read-only user
CREATE USER 'axonflow_reader'@'%' IDENTIFIED BY 'secure_password';
GRANT SELECT ON mydb.* TO 'axonflow_reader'@'%';

-- Read-write user
CREATE USER 'axonflow_writer'@'%' IDENTIFIED BY 'secure_password';
GRANT SELECT, INSERT, UPDATE, DELETE ON mydb.* TO 'axonflow_writer'@'%';

-- Require SSL
ALTER USER 'axonflow_reader'@'%' REQUIRE SSL;
ALTER USER 'axonflow_writer'@'%' REQUIRE SSL;

FLUSH PRIVILEGES;

Troubleshooting

Connection Refused

• Verify host and port are correct
• Check MySQL is running and accepting remote connections
• Verify bind-address in MySQL config allows connections

Access Denied

• Verify username and password
• Check user has correct host permissions ('user'@'host')
• Ensure user has required grants on database

Unknown Database

• Verify database exists: SHOW DATABASES;
• Check user has access to database

TLS/SSL Issues

• For self-signed: Use tls=skip-verify
• For verified SSL: Configure CA certificate
• Check MySQL server has SSL enabled: SHOW VARIABLES LIKE '%ssl%';

Character Encoding Issues

• Use charset=utf8mb4 in DSN
• Ensure database and tables use utf8mb4
• Check collation matches application expectations

Related

• PostgreSQL Connector
• MongoDB Connector
• MCP Overview