select_delivery · Mcp Costco MCP: Risk & Policy

WHAT IT DOES

What select_delivery does on Mcp Costco

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

WHY IT NEEDS A POLICY

Why select_delivery needs a policy

This tool commits a delivery preference to an active order but does not finalize payment or execute destructive operations. It is reversible (the user can select a different delivery method before checkout completes). It falls under Write rather than Execute because it modifies structured e-commerce data rather than triggering external code execution.

From the tool's definition Tool modifies the shopping cart state by setting a delivery method selection, which is a reversible write operation in an e-commerce checkout workflow.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

select_delivery Rate-limited

select_delivery 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": {
    "select_delivery": {
      "limits": [
        {
          "counter": "select_delivery_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 Costco, so you can run agents against it safely.

FAQ

Questions about select_delivery

What does the select_delivery tool do? +

Choose delivery method — home delivery or warehouse pickup. It is categorised as a Write tool in the Mcp Costco MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on select_delivery? +

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

What risk level is select_delivery? +

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

Can I rate-limit select_delivery? +

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

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

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