shuffle · Basic MCP: Risk & Policy

WHAT IT DOES

What shuffle does on Basic

AI agents invoke shuffle to trigger actions in Basic. 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 shuffle needs a policy

Shuffling an array involves executing an algorithm that produces a transformed output based on random state. It has no persistent side effects, doesn't read external data, and doesn't write or delete anything, but it does 'run' a randomization algorithm over supplied data. The blast radius is minimal—at worst, an agent receives a reordered array—so severity is low.

From the tool's definition Randomly shuffle an array (Fisher-Yates algorithm)

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

shuffle Rate-limited

shuffle 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": {
    "shuffle": {
      "limits": [
        {
          "counter": "shuffle_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 Basic, so you can run agents against it safely.

FAQ

Questions about shuffle

What does the shuffle tool do? +

Randomly shuffle an array (Fisher-Yates algorithm). It is categorised as a Execute tool in the Basic MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on shuffle? +

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

What risk level is shuffle? +

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

Can I rate-limit shuffle? +

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

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

shuffle is provided by the Basic MCP server (msilverblatt/basic-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.