connect_database · PostgreSQL MCP Server MCP: Risk & Policy

WHAT IT DOES

What connect_database does on PostgreSQL MCP Server

AI agents invoke connect_database to trigger actions in PostgreSQL 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 connect_database needs a policy

Connecting to a database is not a simple read; it initiates an authenticated session with an external system, consumes resources, and may expose credentials. It is not destructive or financial, but it does execute an external operation whose effects depend on the provided connection arguments (host, credentials, database name).

From the tool's definition 'Connect to a PostgreSQL database' — establishes an external connection to a database system, triggering an external operation with side effects (open network connection, authentication, session creation).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

connect_database Rate-limited

connect_database 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": {
    "connect_database": {
      "limits": [
        {
          "counter": "connect_database_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 PostgreSQL MCP Server, so you can run agents against it safely.

FAQ

Questions about connect_database

What does the connect_database tool do? +

Connect to a PostgreSQL database. It is categorised as a Execute tool in the PostgreSQL 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 connect_database? +

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

What risk level is connect_database? +

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

Can I rate-limit connect_database? +

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

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

connect_database is provided by the PostgreSQL MCP Server MCP server (melihbirim/pg-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.