attach_external_transaction · Keycrm MCP: Risk & Policy

WHAT IT DOES

What attach_external_transaction does on Keycrm

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

WHY IT NEEDS A POLICY

Why attach_external_transaction needs a policy

This tool modifies an existing payment record by attaching external transaction data. It is a write operation (linking/updating a record), not a direct financial transfer, but it affects financial records. Since it modifies data reversibly (an attachment can potentially be removed), Write is the appropriate category rather than Financial.

From the tool's definition Attach an external transaction to an existing payment record

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

attach_external_transaction Rate-limited

attach_external_transaction 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": {
    "attach_external_transaction": {
      "limits": [
        {
          "counter": "attach_external_transaction_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 Keycrm, so you can run agents against it safely.

FAQ

Questions about attach_external_transaction

What does the attach_external_transaction tool do? +

Attach an external transaction to an existing payment record in keyCRM. It is categorised as a Write tool in the Keycrm MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on attach_external_transaction? +

Register the Keycrm MCP server in PolicyLayer and add a rule for attach_external_transaction: 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 Keycrm. Nothing to install.

What risk level is attach_external_transaction? +

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

Can I rate-limit attach_external_transaction? +

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

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

attach_external_transaction is provided by the Keycrm MCP server (ivanklymenko/keycrm-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.