snow_event_handler

Register a script action (sysevent_script_action) that runs when a named platform event fires. Script must be ES5-compatible (no arrow functions, const/let, etc.).

SERVERSerac SOURCEserac-labs/serac

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/serac/snow-event-handler.md

WHAT IT DOES

What snow_event_handler does on Serac

AI agents use snow_event_handler to create or update resources in Serac, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Serac environment.

RISK

Why snow_event_handler is rated Medium

This tool creates a new event handler record (sysevent_script_action) in ServiceNow, which is a Write operation. However, it has high severity because registering arbitrary script actions that execute on platform events can have broad systemic effects — any time the named event fires, the registered script will run, potentially affecting many records, processes, or integrations across the platform.

From the tool's definition Register a script action (sysevent_script_action) that runs when a named platform event fires

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs snow_event_handler safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Serac, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For snow_event_handler, this is the rule to start with:

snow_event_handler Rate-limited

snow_event_handler 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "snow_event_handler": {
      "limits": [
        {
          "counter": "snow_event_handler_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Serac, apply this rule, and every snow_event_handler call is checked against it from then on.

FAQ

Questions about snow_event_handler

What does the snow_event_handler tool do? +

Register a script action (sysevent_script_action) that runs when a named platform event fires. Script must be ES5-compatible (no arrow functions, const/let, etc.). It is categorised as a Write tool in the Serac MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on snow_event_handler? +

Register the Serac MCP server in PolicyLayer and add a rule for snow_event_handler: 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 Serac. Nothing to install.

What risk level is snow_event_handler? +

snow_event_handler is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit snow_event_handler? +

Yes. Add a rate_limit block to the snow_event_handler 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 snow_event_handler completely? +

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

snow_event_handler is provided by the Serac MCP server (serac-labs/serac). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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