set_destination · Mcp Lyft MCP: Risk & Policy

WHAT IT DOES

What set_destination does on Mcp Lyft

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

WHY IT NEEDS A POLICY

Why set_destination needs a policy

This tool writes/modifies ride configuration data (the destination). It is reversible in that the destination can be changed before a ride is confirmed. It does not directly move money or execute code, though it is a precursor to requesting a ride. Classified as Write with medium severity since setting a wrong destination could lead to an unintended ride request.

From the tool's definition "Set the destination for your ride" — modifies the destination parameter of a ride request

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_destination Rate-limited

set_destination 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": {
    "set_destination": {
      "limits": [
        {
          "counter": "set_destination_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 Mcp Lyft, so you can run agents against it safely.

FAQ

Questions about set_destination

What does the set_destination tool do? +

Set the destination for your ride. It is categorised as a Write tool in the Mcp Lyft MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_destination? +

Register the Mcp Lyft MCP server in PolicyLayer and add a rule for set_destination: 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 Mcp Lyft. Nothing to install.

What risk level is set_destination? +

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

Can I rate-limit set_destination? +

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

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

set_destination is provided by the Mcp Lyft MCP server (markswendsen-code/mcp-lyft). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.