check_instance_health

THE RISK

Low Risk

Why check_instance_health needs a policy

This tool queries and retrieves health status and version information from a ServiceNow instance. It performs read-only operations that retrieve system metadata without modifying any data, executing code, or triggering external operations. The blast radius of misuse is minimal — an agent could only gather information about the instance state.

From the tool's definition The tool name is 'check_instance_health' and the description states it 'Run[s] a consolidated health check on a ServiceNow instance. Returns version info' — purely informational retrieval with no modifications, no code execution, and no side effects.

Documented attack patterns abuse exactly the kind of access check_instance_health gives an agent:

POLICY

How to control check_instance_health

PolicyLayer is an MCP gateway — it sits between your AI agents and Now Sdk Ext, and nothing reaches the server without passing your rules. This is the rule we recommend for check_instance_health:

policy.json

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

check_instance_health is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register Now Sdk Ext — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

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EXPLORE

Related tools and policies

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All 86 Now Sdk Ext tools →

Read tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about check_instance_health

What does the check_instance_health tool do? +

Run a consolidated health check on a ServiceNow instance. Returns version info,. It is categorised as a Read tool in the Now Sdk Ext MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on check_instance_health? +

Register the Now Sdk Ext MCP server in PolicyLayer and add a rule for check_instance_health: 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 Now Sdk Ext. Nothing to install.

What risk level is check_instance_health? +

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

Can I rate-limit check_instance_health? +

Yes. Add a rate_limit block to the check_instance_health 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_instance_health completely? +

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

check_instance_health is provided by the Now Sdk Ext MCP server (sonisoft-cnanda/now-sdk-ext-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Now Sdk Ext tool call.

Start from Now Sdk Ext, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →