Creates a new variable (question/field) on a service catalog item's form.
AI agents use create_catalog_item_variable to create or update resources in Snow — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Snow environment.
This tool creates new data structures (form variables) in the ServiceNow service catalog, which is a reversible modification operation. It does not delete data (Destructive), execute arbitrary code (Execute), involve financial transactions (Financial), or merely query data (Read).
From the tool's definition The tool 'Creates a new variable (question/field) on a service catalog item's form' performs a create operation that adds a new field/question to a catalog item, modifying the structure and configuration of the service catalog.
Documented attack patterns abuse exactly the kind of access create_catalog_item_variable gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Snow, and nothing reaches the server without passing your rules. This is the rule we recommend for create_catalog_item_variable:
{
"version": "1",
"default": "deny",
"tools": {
"create_catalog_item_variable": {
"limits": [
{
"counter": "create_catalog_item_variable_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_catalog_item_variable 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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Creates a new variable (question/field) on a service catalog item's form. It is categorised as a Write tool in the Snow MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Snow MCP server in PolicyLayer and add a rule for create_catalog_item_variable: 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 Snow. Nothing to install.
create_catalog_item_variable 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 create_catalog_item_variable 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 create_catalog_item_variable. 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.
create_catalog_item_variable is provided by the Snow MCP server (shunyaai/snow-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Snow, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
88 Snow tools catalogued and risk-classified — across an index of 43,000+ MCP servers.