c2b_register · Africa Payments MCP: Risk & Policy

WHAT IT DOES

What c2b_register does on Africa Payments MCP

AI agents use c2b_register to create or update resources in Africa Payments MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Africa Payments MCP environment.

WHY IT NEEDS A POLICY

Why c2b_register needs a policy

This tool creates or modifies payment configuration by registering callback URLs for receiving payments. While it doesn't move money directly (which would be Financial) or delete data (Destructive), it does durably modify system state in a way that affects payment flows.

From the tool's definition Tool performs registration that modifies configuration state: 'Register C2B URLs for receiving payments directly to your paybill/till' and 'Required for M-Pesa C2B integration.' This creates/configures new payment endpoints rather than executing transactions…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

c2b_register Rate-limited

c2b_register 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": {
    "c2b_register": {
      "limits": [
        {
          "counter": "c2b_register_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 Africa Payments MCP, so you can run agents against it safely.

FAQ

Questions about c2b_register

What does the c2b_register tool do? +

Register C2B (Customer to Business) URLs for receiving payments directly to your paybill/till. Required for M-Pesa C2B integration. It is categorised as a Write tool in the Africa Payments MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on c2b_register? +

Register the Africa Payments MCP server in PolicyLayer and add a rule for c2b_register: 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 Africa Payments MCP. Nothing to install.

What risk level is c2b_register? +

c2b_register is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit c2b_register? +

Yes. Add a rate_limit block to the c2b_register 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 c2b_register completely? +

Set action: deny in the PolicyLayer policy for c2b_register. 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 c2b_register? +

c2b_register is provided by the Africa Payments MCP server (kenyaclaw/africa-payments-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.