addCustomField · Lofty MCP Server MCP: Risk & Policy

WHAT IT DOES

What addCustomField does on Lofty MCP Server

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

WHY IT NEEDS A POLICY

Why addCustomField needs a policy

The tool performs a create-or-update operation on custom field data within the Lofty CRM system. This is a Write category action: it modifies existing data or creates new field values, but the changes are not destructive (can be reversed or overwritten).

From the tool's definition Tool description states 'Add or update a custom field value' — these are write operations that create or modify data reversibly.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

addCustomField Rate-limited

addCustomField 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": {
    "addCustomField": {
      "limits": [
        {
          "counter": "addcustomfield_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Lofty MCP Server, so you can run agents against it safely.

FAQ

Questions about addCustomField

What does the addCustomField tool do? +

Add or update a custom field value. It is categorised as a Write tool in the Lofty 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 addCustomField? +

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

What risk level is addCustomField? +

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

Can I rate-limit addCustomField? +

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

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

addCustomField is provided by the Lofty MCP Server MCP server (nerdsnipe-inc/lofty-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.