rental_add_lease · Excel Finance MCP: Risk & Policy

WHAT IT DOES

What rental_add_lease does on Excel Finance MCP

AI agents use rental_add_lease 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_lease needs a policy

Adding a lease agreement is a reversible write operation that creates new data in the Excel workbook or rental management system. While leases have contractual/financial implications, the tool itself performs data creation rather than moving money or making irreversible deletions.

From the tool's definition Tool description states 'Add a new lease agreement' which creates new data in the rental management system. The server description mentions 'rental property management' as a core function, and this tool creates a new lease record.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

rental_add_lease Rate-limited

rental_add_lease 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_lease": {
      "limits": [
        {
          "counter": "rental_add_lease_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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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_lease

What does the rental_add_lease tool do? +

Add a new lease agreement. 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_lease? +

Register the Excel Finance MCP server in PolicyLayer and add a rule for rental_add_lease: 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_lease? +

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

Can I rate-limit rental_add_lease? +

Yes. Add a rate_limit block to the rental_add_lease 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_lease completely? +

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

rental_add_lease 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.