pg_connections · RedisNexus MCP: Risk & Policy

WHAT IT DOES

What pg_connections does on RedisNexus

AI agents invoke pg_connections to trigger actions in RedisNexus. 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 pg_connections needs a policy

While the tool includes read operations (list active, view stats), the 'kill idle' capability elevates the risk category significantly. Killing PostgreSQL connections is a destructive, disruptive action that terminates active sessions, potentially interrupting in-flight transactions and causing application errors.

From the tool's definition 'kill idle' connections — terminating active database connections is an irreversible disruptive action that can interrupt running transactions and application sessions

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

pg_connections Rate-limited

pg_connections 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": {
    "pg_connections": {
      "limits": [
        {
          "counter": "pg_connections_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 RedisNexus, so you can run agents against it safely.

FAQ

Questions about pg_connections

What does the pg_connections tool do? +

Manage PostgreSQL connections: list active, kill idle, view stats. It is categorised as a Execute tool in the RedisNexus MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on pg_connections? +

Register the RedisNexus MCP server in PolicyLayer and add a rule for pg_connections: 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 RedisNexus. Nothing to install.

What risk level is pg_connections? +

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

Can I rate-limit pg_connections? +

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

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

pg_connections is provided by the RedisNexus MCP server (rajkumar-madhu/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.