stop_preview

THE RISK

High Risk

Why stop_preview needs a policy

This tool executes a command to stop a running process, which falls under Execute category as it performs an action whose effects depend on the state of the system. However, severity is low because stopping a preview server is a benign, easily reversible operation with minimal blast radius—the preview can simply be restarted with no data loss or side effects. It does not modify, delete, or create permanent artifacts.

From the tool's definition Tool name 'stop_preview' and description 'Stop a running Hugo preview server' indicate execution of a command to terminate a process. The verb 'stop' represents an active operation that triggers external system behavior (terminating a server process).

Documented attack patterns abuse exactly the kind of access stop_preview gives an agent:

POLICY

How to control stop_preview

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

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "stop_preview": {
      "limits": [
        {
          "counter": "stop_preview_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

stop_preview 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 Hugo — 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 Hugo tools

Execute build_site Build the Hugo site for production Execute deploy_site Deploy a Hugo site to various platforms Execute start_preview Start Hugo local server for preview Execute install_theme Install a Hugo theme Write create_post Create a new Hugo post Write create_site Create a new Hugo site Write update_theme Update an installed Hugo theme Read check_git_installation Check if Git is installed and get its configuration

All 15 Hugo 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

High-risk tools in Hugo → 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 →

FAQ

Questions about stop_preview

What does the stop_preview tool do? +

Stop a running Hugo preview server. It is categorised as a Execute tool in the Hugo MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on stop_preview? +

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

What risk level is stop_preview? +

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

Can I rate-limit stop_preview? +

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

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

stop_preview is provided by the Hugo MCP server (sunnycloudyang/hugo-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Hugo tool call.

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

CHECK YOUR STACK →