pg_cancel_backend

Cancel a running query (graceful, preferred over terminate).

SERVERPostgreSQL MCP Server SOURCE@neverinfamous/postgres-mcp

High RISK CLASS

Category Execute

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-neverinfamous-postgres-mcp/pg-cancel-backend.md

WHAT IT DOES

What pg_cancel_backend does on PostgreSQL MCP Server

AI agents invoke pg_cancel_backend 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.

RISK

Why pg_cancel_backend is rated High

This tool sends a cancellation signal to a running backend/query process. It triggers an external operation (interrupting a database process) that can affect running transactions and ongoing work. While it's described as 'graceful', it still forcibly stops another process's execution, which can cause partial work to be rolled back and disrupt other users or operations.

From the tool's definition Cancel a running query (graceful, preferred over terminate)

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs pg_cancel_backend safely

PolicyLayer is an MCP gateway: it sits between your AI agents and PostgreSQL MCP Server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For pg_cancel_backend, this is the rule to start with:

pg_cancel_backend Rate-limited

pg_cancel_backend 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_cancel_backend": {
      "limits": [
        {
          "counter": "pg_cancel_backend_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect PostgreSQL MCP Server, apply this rule, and every pg_cancel_backend call is checked against it from then on.

FAQ

Questions about pg_cancel_backend

What does the pg_cancel_backend tool do? +

Cancel a running query (graceful, preferred over terminate). 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 pg_cancel_backend? +

Register the PostgreSQL MCP Server MCP server in PolicyLayer and add a rule for pg_cancel_backend: 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 pg_cancel_backend? +

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

Can I rate-limit pg_cancel_backend? +

Yes. Add a rate_limit block to the pg_cancel_backend 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_cancel_backend completely? +

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

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

KEEP EXPLORING

What pg_cancel_backend does on PostgreSQL MCP Server

Why pg_cancel_backend is rated High

The rule that runs pg_cancel_backend safely

Questions about pg_cancel_backend

More on PostgreSQL MCP Server, and thousands of servers like it.