mod-tidy

THE RISK

High Risk

Why mod-tidy needs a policy

This tool executes a shell command (go mod tidy) that modifies the module dependency files (go.mod and go.sum) by adding and removing entries. While it writes to files, the primary action is executing an external tool/process. The blast radius is medium since it can alter dependency resolution, potentially introducing or removing packages in a project.

From the tool's definition 'Runs go mod tidy to add missing and remove unused module dependencies'

Documented attack patterns abuse exactly the kind of access mod-tidy gives an agent:

POLICY

How to control mod-tidy

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

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "mod-tidy": {
      "limits": [
        {
          "counter": "mod-tidy_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

mod-tidy 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.

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

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Cargo tools

Destructive clean Runs dotnet clean to remove build outputs and returns structured results. Destructive remove Runs Destructive reset Resets the current HEAD to a specified state. Supports soft, mixed, hard, merge, and keep Destructive secret-delete Deletes a repository, organization, or environment GitHub Actions secret. Destructive tag Manages git tags. Supports list (default), create, and delete actions. List returns struct Destructive variable-delete Deletes a repository, organization, or environment GitHub Actions variable. Destructive workspace Manages Terraform workspaces: list, select, create, or delete workspaces. Destructive branch Lists, creates, renames, or deletes branches. Returns structured branch data. Pass

All 202 Cargo tools →

Execute tools on other servers

Android Forensics ADB MCP Server adb_shell_command EMBA-MCP run_emba_scan Frida Game Hacking MCP remove_breakpoint Procmon request_elevation

Go deeper

Govern code and CI agents → Branch allowlists, approval on merges, and rate caps on the build and pipeline tools agents trigger.
High-risk tools in Cargo → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →
PolicyLayer vs alternatives → How deterministic, per-call MCP policy compares with gateways, identity layers, and authorisation platforms.

FAQ

Questions about mod-tidy

What does the mod-tidy tool do? +

Runs go mod tidy to add missing and remove unused module dependencies. 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 mod-tidy? +

Register the Cargo MCP server in PolicyLayer and add a rule for mod-tidy: 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 mod-tidy? +

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

Can I rate-limit mod-tidy? +

Yes. Add a rate_limit block to the mod-tidy 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 mod-tidy completely? +

Set action: deny in the PolicyLayer policy for mod-tidy. 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 mod-tidy? +

mod-tidy 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.

Enforce policy on every Cargo tool call.

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

CHECK YOUR STACK →