query · Mcp Postgres Query MCP: Risk & Policy

WHAT IT DOES

What query does on Mcp Postgres Query

AI agents invoke query to trigger actions in Mcp Postgres Query. 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 query needs a policy

This tool runs arbitrary SQL against a PostgreSQL database. While it mentions parameterized queries for safety (reducing injection risk), it does not restrict the SQL to SELECT statements. An AI agent could issue DROP TABLE, DELETE FROM, UPDATE, or other destructive/modifying statements.

From the tool's definition "Execute a SQL query against the PostgreSQL database" — arbitrary SQL execution including potentially destructive statements like DROP, DELETE, or TRUNCATE

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

query Rate-limited

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": {
    "query": {
      "limits": [
        {
          "counter": "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 Mcp Postgres Query, so you can run agents against it safely.

FAQ

Questions about query

What does the query tool do? +

Execute a SQL query against the PostgreSQL database. Supports parameterized queries for safety. Returns rows and row count. It is categorised as a Execute tool in the Mcp Postgres Query MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on query? +

Register the Mcp Postgres Query MCP server in PolicyLayer and add a rule for 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 Mcp Postgres Query. Nothing to install.

What risk level is query? +

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

Can I rate-limit query? +

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

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

query is provided by the Mcp Postgres Query MCP server (lordbasilaiassistant-sudo/mcp-postgres-query). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.