psql-query · Python MCP: Risk & Policy

WHAT IT DOES

What psql-query does on Python

AI agents invoke psql-query to trigger actions in Python. 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 psql-query needs a policy

This tool runs arbitrary SQL queries against a PostgreSQL database. It can execute any SQL including destructive operations (DROP, DELETE, TRUNCATE) or data exfiltration. The blast radius is critical since an AI agent could misuse it to destroy or leak entire databases.

From the tool's definition Executes a PostgreSQL query via psql

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

psql-query Rate-limited

psql-query 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": {
    "psql-query": {
      "limits": [
        {
          "counter": "psql-query_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 Python, so you can run agents against it safely.

FAQ

Questions about psql-query

What does the psql-query tool do? +

Executes a PostgreSQL query via psql and returns structured tabular output. It is categorised as a Execute tool in the Python MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on psql-query? +

Register the Python MCP server in PolicyLayer and add a rule for psql-query: 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 Python. Nothing to install.

What risk level is psql-query? +

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

Can I rate-limit psql-query? +

Yes. Add a rate_limit block to the psql-query 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 psql-query completely? +

Set action: deny in the PolicyLayer policy for psql-query. 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 psql-query? +

psql-query is provided by the Python MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

// THE FULL RECORD

psql-query is one line of Python's registry record.

The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.

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