vapi_end_call · Mcp Vapi MCP: Risk & Policy

WHAT IT DOES

What vapi_end_call does on Mcp Vapi

AI agents invoke vapi_end_call to trigger actions in Mcp Vapi. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why vapi_end_call needs a policy

This tool triggers an external operation (terminating an active voice call) that has real-world side effects. While it doesn't delete data, it forcibly ends an ongoing call, which is an irreversible action on a live session.

From the tool's definition Force-end an active Vapi call. Useful if a call gets stuck or needs to be terminated from a workflow.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

vapi_end_call Rate-limited

vapi_end_call stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "vapi_end_call": {
      "limits": [
        {
          "counter": "vapi_end_call_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about vapi_end_call

What does the vapi_end_call tool do? +

Force-end an active Vapi call. Useful if a call gets stuck or needs to be terminated from a workflow. It is categorised as a Execute tool in the Mcp Vapi MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on vapi_end_call? +

Register the Mcp Vapi MCP server in PolicyLayer and add a rule for vapi_end_call: 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 Mcp Vapi. Nothing to install.

What risk level is vapi_end_call? +

vapi_end_call is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit vapi_end_call? +

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

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

vapi_end_call is provided by the Mcp Vapi MCP server (adhirajhangal/mcp-vapi). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.