alter_table · MCP Database Server MCP: Risk & Policy

WHAT IT DOES

What alter_table does on MCP Database Server

AI agents use alter_table to create or update resources in MCP Database Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your MCP Database Server environment.

WHY IT NEEDS A POLICY

Why alter_table needs a policy

alter_table modifies table definitions through schema operations (add/rename columns). These are Write operations because they create or modify data structures reversibly. While schema changes can have broad impact (high severity), they remain in the Write category since ALTER TABLE operations are not destructive and can typically be reversed with subsequent ALTER operations.

From the tool's definition Tool description states 'Modify existing table schema (add columns, rename tables, etc.)' — this performs reversible modifications to database structures. The action is schema alteration, not deletion or destruction.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

alter_table Rate-limited

alter_table 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.

View as policy code

policy.json

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

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PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches MCP Database Server, so you can run agents against it safely.

FAQ

Questions about alter_table

What does the alter_table tool do? +

Modify existing table schema (add columns, rename tables, etc.). It is categorised as a Write tool in the MCP Database 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 alter_table? +

Register the MCP Database Server MCP server in PolicyLayer and add a rule for alter_table: 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 Database Server. Nothing to install.

What risk level is alter_table? +

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

Can I rate-limit alter_table? +

Yes. Add a rate_limit block to the alter_table 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 alter_table completely? +

Set action: deny in the PolicyLayer policy for alter_table. 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 alter_table? +

alter_table is provided by the MCP Database Server MCP server (suparn7/mcpserverwithsql). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.