AI agents call simple_echo to retrieve information from Executor without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This is a basic echo/reflection function that retrieves and returns data with no modification, creation, deletion, or external operations. It poses minimal security risk as it cannot alter state or trigger actions. Classified as Read with low severity.
From the tool's definition Tool name 'simple_echo' and description 'Echoes a value without elicitation' indicate a pure reflection/output operation that returns input data unchanged without side effects.
Documented attack patterns abuse exactly the kind of access simple_echo gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Executor, and nothing reaches the server without passing your rules. This is the rule we recommend for simple_echo:
{
"version": "1",
"default": "deny",
"tools": {
"simple_echo": {}
}
}simple_echo is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Echoes a value without elicitation. It is categorised as a Read tool in the Executor MCP Server, which means it retrieves data without modifying state.
Register the Executor MCP server in PolicyLayer and add a rule for simple_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 Executor. Nothing to install.
simple_echo is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the simple_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.
Set action: deny in the PolicyLayer policy for simple_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.
simple_echo is provided by the Executor MCP server (rhyssullivan/executor). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 29 Executor tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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29 Executor tools catalogued and risk-classified — across an index of 42,500+ MCP servers.