send_to_webhook

THE RISK

High Risk

Why send_to_webhook needs a policy

This tool triggers an external HTTP operation (POST request) to a remote endpoint. It executes an outbound network action whose effects depend on the arguments (destination URL and payload), making it Execute category. Misuse could involve sending arbitrary data to external services or exfiltrating information.

From the tool's definition Send a POST request with JSON data to a webhook.site endpoint

Documented attack patterns abuse exactly the kind of access send_to_webhook gives an agent:

POLICY

How to control send_to_webhook

PolicyLayer is an MCP gateway — it sits between your AI agents and Webhook Site MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for send_to_webhook:

policy.json

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

send_to_webhook 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.

Create a free account and register Webhook Site MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Webhook Site MCP Server tools

Destructive delete_all_requests Delete all requests from a webhook, optionally filtered by date range or query. Destructive delete_request Delete a specific request from a webhook. Destructive delete_webhook Delete a webhook.site endpoint and all its data. Execute generate_ssrf_payload Generate SSRF (Server-Side Request Forgery) test payloads for bug bounty testing. Creates Execute generate_xss_callback Generate XSS (Cross-Site Scripting) callback payloads for bug bounty testing. Creates Java Execute send_multiple_requests Send multiple requests to a webhook in batch. Useful for load testing or sending multiple Write create_webhook Create a new webhook.site endpoint. Returns the unique token/URL for the webhook. Write create_webhook_with_config Create a new webhook.site endpoint with custom configuration (response content, status, ti

All 23 Webhook Site MCP Server tools →

Execute tools on other servers

Android Forensics ADB MCP Server adb_shell_command EMBA-MCP run_emba_scan Frida Game Hacking MCP remove_breakpoint Procmon request_elevation

Go deeper

High-risk tools in Webhook Site MCP Server → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about send_to_webhook

What does the send_to_webhook tool do? +

Send a POST request with JSON data to a webhook.site endpoint. It is categorised as a Execute tool in the Webhook Site MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on send_to_webhook? +

Register the Webhook Site MCP Server MCP server in PolicyLayer and add a rule for send_to_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 Webhook Site MCP Server. Nothing to install.

What risk level is send_to_webhook? +

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

Can I rate-limit send_to_webhook? +

Yes. Add a rate_limit block to the send_to_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 send_to_webhook completely? +

Set action: deny in the PolicyLayer policy for send_to_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 send_to_webhook? +

send_to_webhook is provided by the Webhook Site MCP Server MCP server (zebbern/webhook-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Webhook Site MCP Server tool call.

Start from Webhook Site MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →