xor_cipher · Crypto Tools MCP Server MCP: Risk & Policy

WHAT IT DOES

What xor_cipher does on Crypto Tools MCP Server

AI agents invoke xor_cipher to trigger actions in Crypto Tools MCP Server. 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 xor_cipher needs a policy

This tool performs a cryptographic operation (XOR cipher) on text, which is an execution of a transformation algorithm. It does not read from external sources, write to storage, or destroy data — it processes input and returns output. XOR is a symmetric, reversible cipher, so it's not destructive.

From the tool's definition XOR encrypt/decrypt text with a key

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

xor_cipher Rate-limited

xor_cipher 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": {
    "xor_cipher": {
      "limits": [
        {
          "counter": "xor_cipher_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 Crypto Tools MCP Server, so you can run agents against it safely.

FAQ

Questions about xor_cipher

What does the xor_cipher tool do? +

XOR encrypt/decrypt text with a key. It is categorised as a Execute tool in the Crypto Tools 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 xor_cipher? +

Register the Crypto Tools MCP Server MCP server in PolicyLayer and add a rule for xor_cipher: 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 Crypto Tools MCP Server. Nothing to install.

What risk level is xor_cipher? +

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

Can I rate-limit xor_cipher? +

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

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

xor_cipher is provided by the Crypto Tools MCP Server MCP server (marc-shade/crypto-tools-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.