High Risk →

bundle-exec

Executes a command in the context of the Gemfile bundle using

How to control bundle-exec ↓

What bundle-exec does on Make

AI agents invoke bundle-exec to trigger actions in Make. 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.

High Risk

Why bundle-exec needs a policy

bundle exec runs arbitrary commands in the Gemfile bundle context, meaning an AI agent could execute any Ruby or system command with the permissions of the current user. The blast radius is high as it enables arbitrary code execution.

From the tool's definition 'Executes a command in the context of the Gemfile bundle using' — the word 'Executes' and 'command' confirm arbitrary command execution within a bundled Ruby environment

Documented attack patterns abuse exactly the kind of access bundle-exec gives an agent:

How to control bundle-exec

PolicyLayer is an MCP gateway — it sits between your AI agents and Make, and nothing reaches the server without passing your rules. This is the rule we recommend for bundle-exec:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "bundle-exec": {
      "limits": [
        {
          "counter": "bundle-exec_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

bundle-exec 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.

  1. Create a free account and register Make — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
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Related tools and policies

Go deeper

Questions about bundle-exec

What does the bundle-exec tool do? +

Executes a command in the context of the Gemfile bundle using. It is categorised as a Execute tool in the Make MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on bundle-exec? +

Register the Make MCP server in PolicyLayer and add a rule for bundle-exec: 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 Make. Nothing to install.

What risk level is bundle-exec? +

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

Can I rate-limit bundle-exec? +

Yes. Add a rate_limit block to the bundle-exec 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 bundle-exec completely? +

Set action: deny in the PolicyLayer policy for bundle-exec. 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 bundle-exec? +

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

Enforce policy on every Make tool call.

Start from Make, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

Free to start. No card required.

202 Make tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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