db_create_function · Database MCP Server MCP: Risk & Policy

WHAT IT DOES

What db_create_function does on Database MCP Server

AI agents invoke db_create_function to trigger actions in Database MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why db_create_function needs a policy

Creating a database function is an Execute-category action because it introduces executable code into the database environment. While the act of creation is Write-like, the primary risk is that the function can contain arbitrary SQL/PL code that executes with database privileges. Misuse could introduce malicious logic, privilege escalation, or destructive operations packaged as a reusable function.

From the tool's definition 'Create a function' — creates a stored function in the database that can later be executed

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

db_create_function Rate-limited

db_create_function stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "db_create_function": {
      "limits": [
        {
          "counter": "db_create_function_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about db_create_function

What does the db_create_function tool do? +

Create a function. It is categorised as a Execute tool in the Database MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on db_create_function? +

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

What risk level is db_create_function? +

db_create_function is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit db_create_function? +

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

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

db_create_function is provided by the Database MCP Server MCP server (roilanrodriguez55/database-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.