add_column

THE RISK

Medium Risk

Why add_column needs a policy

This tool modifies database schema by adding columns to tables, which is a reversible write operation. While it alters table structure, it does not delete or overwrite existing data (making it Write rather than Destructive). The high severity reflects the potential for disruption to dependent applications and queries if columns are added with incorrect types or constraints.

From the tool's definition Tool name 'add_column' and description 'Add a new column to existing table' indicate a schema modification operation that creates new database structure.

Documented attack patterns abuse exactly the kind of access add_column gives an agent:

POLICY

How to control add_column

PolicyLayer is an MCP gateway — it sits between your AI agents and MCP-MongoDB-MySQL-Server, and nothing reaches the server without passing your rules. This is the rule we recommend for add_column:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "add_column": {
      "limits": [
        {
          "counter": "add_column_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

add_column stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

Create a free account and register MCP-MongoDB-MySQL-Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More MCP-MongoDB-MySQL-Server tools

Destructive mongodb_delete Delete documents from a MongoDB collection Execute execute Execute an INSERT, UPDATE, or DELETE query Execute connect_mongodb Connect to MongoDB database using URL or config Write create_table Create a new table in the database Write mongodb_create_collection Create a new collection in MongoDB Write mongodb_insert Insert documents into a MongoDB collection Write mongodb_update Update documents in a MongoDB collection Read describe_table Get table structure

All 14 MCP-MongoDB-MySQL-Server tools →

Write tools on other servers

M-Team MCP Server download_torrent YouTube MCP Server generate_video_title Android Forensics ADB MCP Server combine_reports 0xarchive web3_signup

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about add_column

What does the add_column tool do? +

Add a new column to existing table. It is categorised as a Write tool in the MCP-MongoDB-MySQL-Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add_column? +

Register the MCP-MongoDB-MySQL-Server MCP server in PolicyLayer and add a rule for add_column: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches MCP-MongoDB-MySQL-Server. Nothing to install.

What risk level is add_column? +

add_column is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit add_column? +

Yes. Add a rate_limit block to the add_column rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block add_column completely? +

Set action: deny in the PolicyLayer policy for add_column. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides add_column? +

add_column is provided by the MCP-MongoDB-MySQL-Server MCP server (yaoxiaolinglong/mcp-mongodb-mysql-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MCP-MongoDB-MySQL-Server tool call.

Start from MCP-MongoDB-MySQL-Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →