AI agents use add_comment to create or update resources in ServiceNow MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your ServiceNow MCP Server environment.
The tool creates or modifies data in a reversible manner (comments can be edited or deleted), fitting the Write category. Severity is medium because comment injection could alter audit trails, affect incident management workflows, or inject malicious content into work records, but does not cause irreversible data loss or financial impact.
From the tool's definition Tool name 'add_comment' combined with sibling tools including 'add_work_notes', 'create_incident', 'update_incident', and 'update_script' indicates data modification capability. The server description states it enables 'access and manipulate ServiceNow data'.
Documented attack patterns abuse exactly the kind of access add_comment gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and ServiceNow MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for add_comment:
{
"version": "1",
"default": "deny",
"tools": {
"add_comment": {
"limits": [
{
"counter": "add_comment_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}add_comment stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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add_comment. It is categorised as a Write tool in the ServiceNow MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the ServiceNow MCP Server MCP server in PolicyLayer and add a rule for add_comment: 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 ServiceNow MCP Server. Nothing to install.
add_comment is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the add_comment 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.
Set action: deny in the PolicyLayer policy for add_comment. 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.
add_comment is provided by the ServiceNow MCP Server MCP server (michaelbuckner/servicenow-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from ServiceNow MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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10 ServiceNow MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.