package-clean · Cargo MCP: Risk & Policy

WHAT IT DOES

What package-clean does on Cargo

AI agents invoke package-clean to trigger actions in Cargo. 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 package-clean needs a policy

The tool executes a Swift package management command that removes build artifacts. While the operation is reversible (artifacts can be rebuilt), it is an active command execution rather than a read operation. The blast radius is low because cleaning build artifacts is a routine, low-risk operation with no data loss or system compromise.

From the tool's definition Tool description states it "Cleans Swift package build artifacts" — this invokes a package management operation (swift package clean) that triggers external commands with side effects on the local filesystem.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

package-clean Rate-limited

package-clean 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": {
    "package-clean": {
      "limits": [
        {
          "counter": "package-clean_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 Cargo, so you can run agents against it safely.

FAQ

Questions about package-clean

What does the package-clean tool do? +

Cleans Swift package build artifacts and returns structured result. It is categorised as a Execute tool in the Cargo MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on package-clean? +

Register the Cargo MCP server in PolicyLayer and add a rule for package-clean: 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 Cargo. Nothing to install.

What risk level is package-clean? +

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

Can I rate-limit package-clean? +

Yes. Add a rate_limit block to the package-clean 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 package-clean completely? +

Set action: deny in the PolicyLayer policy for package-clean. 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 package-clean? +

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