update_receipt · CoupleHub MCP Server MCP: Risk & Policy

WHAT IT DOES

What update_receipt does on CoupleHub MCP Server

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

WHY IT NEEDS A POLICY

Why update_receipt needs a policy

This tool modifies existing receipt metadata, which is a reversible write operation. It does not delete data (Destructive), execute arbitrary code (Execute), or involve financial transactions (Financial). The scope is limited to metadata updates within a shared household app, posing low risk even if misused by an agent—at worst, receipt information would be inaccurate but recoverable.

From the tool's definition Tool name 'update_receipt' and description 'Update metadata after parsing photo' indicate modification of receipt data. The context suggests this updates receipt records (likely expense/purchase information) after initial parsing.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_receipt Rate-limited

update_receipt 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": {
    "update_receipt": {
      "limits": [
        {
          "counter": "update_receipt_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 CoupleHub MCP Server, so you can run agents against it safely.

FAQ

Questions about update_receipt

What does the update_receipt tool do? +

RECEIPT STEP 2. Update metadata after parsing photo. It is categorised as a Write tool in the CoupleHub 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 update_receipt? +

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

What risk level is update_receipt? +

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

Can I rate-limit update_receipt? +

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

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

update_receipt is provided by the CoupleHub MCP Server MCP server (uczesieweba/couplehub-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.