Rejects a change request. This finds the current user's approval record
AI agents use reject_change 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.
Rejecting a change request modifies the state of a ServiceNow record reversibly (a rejected change could theoretically be re-submitted or re-approved), but has significant operational impact as it blocks planned infrastructure/application changes. This is a Write operation rather than Destructive because the underlying data is not deleted and the action can be undone through re-submission.
From the tool's definition Tool name 'reject_change' and description 'Rejects a change request' indicates modification of change request state/status. The phrase 'finds the current user's approval record' confirms it operates on existing records by updating their approval status.
Documented attack patterns abuse exactly the kind of access reject_change 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 reject_change:
{
"version": "1",
"default": "deny",
"tools": {
"reject_change": {
"limits": [
{
"counter": "reject_change_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}reject_change 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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Rejects a change request. This finds the current user's approval record. 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 reject_change: 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.
reject_change 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 reject_change 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 reject_change. 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.
reject_change 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.
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88 Snow tools catalogued and risk-classified — across an index of 43,000+ MCP servers.