create_webhook · SpherePay MCP: Risk & Policy

WHAT IT DOES

What create_webhook does on SpherePay

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

WHY IT NEEDS A POLICY

Why create_webhook needs a policy

Webhook creation modifies system configuration by adding new callback endpoints. While not immediately destructive or directly moving money, it creates infrastructure that could redirect financial events or notifications to attacker-controlled servers.

From the tool's definition Tool named 'create_webhook' on a financial services server (SpherePay); webhook creation typically involves writing configuration that enables external callbacks, often for payment notifications or event handling.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_webhook Rate-limited

create_webhook 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": {
    "create_webhook": {
      "limits": [
        {
          "counter": "create_webhook_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches SpherePay, so you can run agents against it safely.

FAQ

Questions about create_webhook

What does the create_webhook tool do? +

create_webhook. It is categorised as a Write tool in the SpherePay MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_webhook? +

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

What risk level is create_webhook? +

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

Can I rate-limit create_webhook? +

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

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

create_webhook is provided by the SpherePay MCP server (danchev/spherepay-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.