invoices_update_custom_fields

A write tool on the ServiceTitan MCP server.

SERVERServiceTitan MCP Server SOURCEjordandalton/servicetitanmcpserver

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/jordandalton-servicetitanmcpserver/invoices-update-custom-fields.md

WHAT IT DOES

What invoices_update_custom_fields does on ServiceTitan MCP Server

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

RISK

Why invoices_update_custom_fields is rated Medium

This tool modifies invoice records by updating custom fields. While the description is empty, the tool name combined with the ServiceTitan context (a platform for managing invoices, payments, and business operations) indicates Write-level capability.

From the tool's definition Tool name 'invoices_update_custom_fields' explicitly indicates modification of invoice data. The 'update' verb in the name and the context of sibling tools (activities_update, adjustments_update) on a financial service platform (ServiceTitan is business…

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs invoices_update_custom_fields safely

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

invoices_update_custom_fields Rate-limited

invoices_update_custom_fields 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": {
    "invoices_update_custom_fields": {
      "limits": [
        {
          "counter": "invoices_update_custom_fields_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 ServiceTitan MCP Server, apply this rule, and every invoices_update_custom_fields call is checked against it from then on.

FAQ

Questions about invoices_update_custom_fields

What does the invoices_update_custom_fields tool do? +

invoices_update_custom_fields is a write tool on the ServiceTitan MCP Server MCP server. It is categorised as a Write tool in the ServiceTitan MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on invoices_update_custom_fields? +

Register the ServiceTitan MCP Server MCP server in PolicyLayer and add a rule for invoices_update_custom_fields: 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 ServiceTitan MCP Server. Nothing to install.

What risk level is invoices_update_custom_fields? +

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

Can I rate-limit invoices_update_custom_fields? +

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

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

invoices_update_custom_fields is provided by the ServiceTitan MCP Server MCP server (jordandalton/servicetitanmcpserver). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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