db_create_user · Database MCP Server MCP: Risk & Policy

WHAT IT DOES

What db_create_user does on Database MCP Server

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

WHY IT NEEDS A POLICY

Why db_create_user needs a policy

Creating a database user is a Write operation: it creates a new principal with LOGIN capability, modifying the database's security posture and access control. While reversible (the user can be dropped), it is a significant structural change that grants new authentication credentials and permissions.

From the tool's definition Tool name is 'db_create_user' and description states 'Create a database user (role with LOGIN)' — this creates a new database role with login privileges, a reversible but consequential modification to database access control.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

db_create_user Rate-limited

db_create_user 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": {
    "db_create_user": {
      "limits": [
        {
          "counter": "db_create_user_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 Database MCP Server, so you can run agents against it safely.

FAQ

Questions about db_create_user

What does the db_create_user tool do? +

Create a database user (role with LOGIN). It is categorised as a Write tool in the Database MCP 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 db_create_user? +

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

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

Can I rate-limit db_create_user? +

Yes. Add a rate_limit block to the db_create_user 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_user completely? +

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

db_create_user 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.