s4_echo_plain

Echo a code back. Call with any string code.

SERVERCrow SOURCEkh0pper/crow

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/kh0pper-crow/s4-echo-plain.md

WHAT IT DOES

What s4_echo_plain does on Crow

AI agents call s4_echo_plain to retrieve information from Crow without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why s4_echo_plain is rated Low

An echo function reflects the input back to the caller with no data modification, deletion, or external operations. It is a read/passthrough operation with minimal blast radius.

From the tool's definition 'Echo a code back. Call with any string code.' - simply echoes/returns input without side effects

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs s4_echo_plain safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Crow, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For s4_echo_plain, this is the rule to start with:

s4_echo_plain Allowed

s4_echo_plain is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "s4_echo_plain": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Crow, apply this rule, and every s4_echo_plain call is checked against it from then on.

FAQ

Questions about s4_echo_plain

What does the s4_echo_plain tool do? +

Echo a code back. Call with any string code. It is categorised as a Read tool in the Crow MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on s4_echo_plain? +

Register the Crow MCP server in PolicyLayer and add a rule for s4_echo_plain: 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 Crow. Nothing to install.

What risk level is s4_echo_plain? +

s4_echo_plain is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit s4_echo_plain? +

Yes. Add a rate_limit block to the s4_echo_plain 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 s4_echo_plain completely? +

Set action: deny in the PolicyLayer policy for s4_echo_plain. 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 s4_echo_plain? +

s4_echo_plain is provided by the Crow MCP server (kh0pper/crow). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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