check_postgres

Connect to a PostgreSQL server and read the server version from the startup response. Does not authenticate. Useful for verifying database server reachability and version.

SERVERMcp Nettools SOURCEaaronckj/mcp-nettools

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/aaronckj-mcp-nettools/check-postgres.md

WHAT IT DOES

What check_postgres does on Mcp Nettools

AI agents call check_postgres to retrieve information from Mcp Nettools without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why check_postgres is rated Low

This tool only retrieves metadata (PostgreSQL server version) from a database connection without authentication, side effects, or code execution. It is a passive reconnaissance action with minimal blast radius - at worst it confirms a service is running and its version. The lack of authentication and explicit read-only nature (version from startup response) places it firmly in the Read category.

From the tool's definition "Connect to a PostgreSQL server and read the server version from the startup response. Does not authenticate." - the tool reads/queries version information without modifying data or executing commands.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs check_postgres safely

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

check_postgres Allowed

check_postgres is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "check_postgres": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Mcp Nettools, apply this rule, and every check_postgres call is checked against it from then on.

FAQ

Questions about check_postgres

What does the check_postgres tool do? +

Connect to a PostgreSQL server and read the server version from the startup response. Does not authenticate. Useful for verifying database server reachability and version. It is categorised as a Read tool in the Mcp Nettools MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on check_postgres? +

Register the Mcp Nettools MCP server in PolicyLayer and add a rule for check_postgres: 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 Nettools. Nothing to install.

What risk level is check_postgres? +

check_postgres is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit check_postgres? +

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

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

check_postgres is provided by the Mcp Nettools MCP server (aaronckj/mcp-nettools). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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