shell

Makes packages available in the environment and optionally runs a command. Returns stdout, stderr, exit code, and duration.

SERVERGo SOURCEDave-London/Pare

High RISK CLASS

Category Execute

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-dave-london-go/shell.md

WHAT IT DOES

What shell does on Go

AI agents invoke shell to trigger actions in Go. 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.

RISK

Why shell is rated High

This tool executes arbitrary shell commands in the environment. The ability to run arbitrary commands represents the highest risk of misuse — an AI agent could run destructive, data-exfiltrating, or system-compromising commands.

From the tool's definition 'optionally runs a command. Returns stdout, stderr, exit code, and duration'

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs shell safely

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

shell Rate-limited

shell 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": {
    "shell": {
      "limits": [
        {
          "counter": "shell_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL → Instant setup, no code required.

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

FAQ

Questions about shell

What does the shell tool do? +

Makes packages available in the environment and optionally runs a command. Returns stdout, stderr, exit code, and duration. It is categorised as a Execute tool in the Go MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on shell? +

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

What risk level is shell? +

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

Can I rate-limit shell? +

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

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

shell is provided by the Go MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

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