db_create_extension · Database MCP Server MCP: Risk & Policy

WHAT IT DOES

What db_create_extension does on Database MCP Server

AI agents invoke db_create_extension 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_extension needs a policy

Installing a database extension is an Execute-level action: it runs a DDL command (CREATE EXTENSION) that loads and registers native code/modules into the database server. While not purely destructive, it modifies the database environment in a way that can have wide-ranging effects (new privileges, system catalogs changes, native code execution), making it high severity if misused.

From the tool's definition 'Install an extension' — installs a PostgreSQL extension into the database, which executes server-side code and can introduce new functions, data types, and capabilities

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

db_create_extension Rate-limited

db_create_extension 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_extension": {
      "limits": [
        {
          "counter": "db_create_extension_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_extension

What does the db_create_extension tool do? +

Install an extension. 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_extension? +

Register the Database MCP Server MCP server in PolicyLayer and add a rule for db_create_extension: 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_extension? +

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

Can I rate-limit db_create_extension? +

Yes. Add a rate_limit block to the db_create_extension 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_extension completely? +

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

db_create_extension 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.