echo

THE RISK

Low Risk

Why echo needs a policy

This is a simple echo tool that returns the input message unchanged. It has no side effects, does not read external data, does not execute code, and does not modify anything. It is purely a passthrough/reflection utility.

From the tool's definition 入力されたメッセージをそのまま返します (returns the input message as-is)

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

POLICY

How to control echo

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

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "echo": {
      "limits": [
        {
          "counter": "echo_rate",
          "window": "minute",
          "max": 60,
          "scope": "grant"
        }
      ]
    }
  }
}

echo gets a rate cap, and everything else on the server is denied unless you say otherwise.

Create a free account and register Playwright 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.

SET A RULE FOR THIS TOOL →

Free to start. No card required.

EXPLORE

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Tool risk categories → How PolicyLayer classifies MCP tools by what they can do.
MCP tool → What an MCP tool is and how clients discover and call it.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about echo

What does the echo tool do? +

入力されたメッセージをそのまま返します. It is categorised as a Other tool in the Playwright MCP Server MCP Server, which means it performs auxiliary operations.

How do I enforce a policy on echo? +

Register the Playwright MCP Server MCP server in PolicyLayer and add a rule for echo: 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 Playwright MCP Server. Nothing to install.

What risk level is echo? +

echo is a Other tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit echo? +

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

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

echo is provided by the Playwright MCP Server MCP server (showfive/playwright-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 Playwright MCP Server tool call.

Start from Playwright 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 →