rental_add_property · Excel Finance MCP: Risk & Policy

WHAT IT DOES

What rental_add_property does on Excel Finance MCP

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

WHY IT NEEDS A POLICY

Why rental_add_property needs a policy

This tool creates a new financial asset record (rental property) in what appears to be a financial tracking system. It is reversible (property can be deleted/removed later), so it falls under Write rather than Destructive. Severity is medium because adding a property with incorrect details could lead to inaccurate financial reporting or calculations, but the impact is limited to one property record.

From the tool's definition Tool name: 'rental_add_property'; description: 'Add a new rental property to the system' — the verb 'Add' and 'new' indicate creation of a financial record. Server context involves 'rental property management' and 'financial calculations'.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

rental_add_property Rate-limited

rental_add_property 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": {
    "rental_add_property": {
      "limits": [
        {
          "counter": "rental_add_property_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 Excel Finance MCP, so you can run agents against it safely.

FAQ

Questions about rental_add_property

What does the rental_add_property tool do? +

Add a new rental property to the system. It is categorised as a Write tool in the Excel Finance MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on rental_add_property? +

Register the Excel Finance MCP server in PolicyLayer and add a rule for rental_add_property: 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 Excel Finance MCP. Nothing to install.

What risk level is rental_add_property? +

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

Can I rate-limit rental_add_property? +

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

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

rental_add_property is provided by the Excel Finance MCP server (jeremycharlesgillespie/excel-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.