Create a new update set. IMPORTANT: This creates a new update set on the instance.
AI agents use create_update_set to create or update resources in Now Sdk Ext — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Now Sdk Ext environment.
This tool creates a new update set, which is a configuration object in ServiceNow. While update sets can be deleted or reverted, the primary action is creation of a persistent object on the instance. This is a Write operation (not Destructive, since update sets can be removed; not Execute, since it doesn't run arbitrary code).
From the tool's definition Tool description explicitly states 'Create a new update set' and emphasizes 'This creates a new update set on the instance.' The word 'create' combined with the emphasis on instance-level persistence indicates reversible data creation.
Documented attack patterns abuse exactly the kind of access create_update_set gives an agent:
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 create_update_set:
{
"version": "1",
"default": "deny",
"tools": {
"create_update_set": {
"limits": [
{
"counter": "create_update_set_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_update_set 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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Create a new update set. IMPORTANT: This creates a new update set on the instance. It is categorised as a Write tool in the Now Sdk Ext MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Now Sdk Ext MCP server in PolicyLayer and add a rule for create_update_set: 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.
create_update_set 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_update_set 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_update_set. 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_update_set 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.
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.
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86 Now Sdk Ext tools catalogued and risk-classified — across an index of 43,000+ MCP servers.