mpesa_c2b · Africa Payments MCP: Risk & Policy

WHAT IT DOES

What mpesa_c2b does on Africa Payments MCP

AI agents use mpesa_c2b 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 mpesa_c2b needs a policy

This tool registers callback URLs (Customer-to-Business) to receive M-Pesa payment notifications. It modifies configuration/endpoint settings on the M-Pesa platform — a reversible write operation. It does not itself move money, but misconfiguration could redirect payment notifications to a malicious endpoint, hence medium severity.

From the tool's definition Register C2B URLs for receiving M-Pesa payments directly

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mpesa_c2b Rate-limited

mpesa_c2b 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": {
    "mpesa_c2b": {
      "limits": [
        {
          "counter": "mpesa_c2b_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 mpesa_c2b

What does the mpesa_c2b tool do? +

Register C2B URLs for receiving M-Pesa payments directly. 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 mpesa_c2b? +

Register the Africa Payments MCP server in PolicyLayer and add a rule for mpesa_c2b: 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 mpesa_c2b? +

mpesa_c2b is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit mpesa_c2b? +

Yes. Add a rate_limit block to the mpesa_c2b 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 mpesa_c2b completely? +

Set action: deny in the PolicyLayer policy for mpesa_c2b. 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 mpesa_c2b? +

mpesa_c2b 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.