preview_blog · Hexo Blog MCP Server MCP: Risk & Policy

WHAT IT DOES

What preview_blog does on Hexo Blog MCP Server

AI agents invoke preview_blog to trigger actions in Hexo Blog MCP Server. 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 preview_blog needs a policy

This tool launches a local server process (Hexo dev server on port 4000), which is an external operation/execution. It doesn't just read data — it starts a running service. This fits Execute, not Read. Misuse could tie up ports or expose local content, giving it medium severity.

From the tool's definition 启动 Hexo 本地预览服务器（localhost:4000）— 'starts' a local preview server, triggering an external process/service

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

preview_blog Rate-limited

preview_blog 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": {
    "preview_blog": {
      "limits": [
        {
          "counter": "preview_blog_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 Hexo Blog MCP Server, so you can run agents against it safely.

FAQ

Questions about preview_blog

What does the preview_blog tool do? +

启动 Hexo 本地预览服务器（localhost:4000）. It is categorised as a Execute tool in the Hexo Blog MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on preview_blog? +

Register the Hexo Blog MCP Server MCP server in PolicyLayer and add a rule for preview_blog: 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 Hexo Blog MCP Server. Nothing to install.

What risk level is preview_blog? +

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

Can I rate-limit preview_blog? +

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

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

preview_blog is provided by the Hexo Blog MCP Server MCP server (leejersey/hexo-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.