live2d_expression · Live2d To Agent MCP: Risk & Policy

WHAT IT DOES

What live2d_expression does on Live2d To Agent

AI agents invoke live2d_expression to trigger actions in Live2d To Agent. 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 live2d_expression needs a policy

This tool triggers an external operation on a running Live2D application, changing its displayed expression. It is not a simple data read or write to a database, but rather an action that controls an external process. The blast radius is low since it only affects a cosmetic desktop pet animation.

From the tool's definition 切换 Live2D 表情 (Switch Live2D expression) — triggers an external operation on the Live2D desktop pet application

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

live2d_expression Rate-limited

live2d_expression 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": {
    "live2d_expression": {
      "limits": [
        {
          "counter": "live2d_expression_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 Live2d To Agent, so you can run agents against it safely.

FAQ

Questions about live2d_expression

What does the live2d_expression tool do? +

切换 Live2D 表情。从模型定义的表情中选择。. It is categorised as a Execute tool in the Live2d To Agent MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on live2d_expression? +

Register the Live2d To Agent MCP server in PolicyLayer and add a rule for live2d_expression: 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 Live2d To Agent. Nothing to install.

What risk level is live2d_expression? +

live2d_expression is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit live2d_expression? +

Yes. Add a rate_limit block to the live2d_expression 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 live2d_expression completely? +

Set action: deny in the PolicyLayer policy for live2d_expression. 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 live2d_expression? +

live2d_expression is provided by the Live2d To Agent MCP server (lmy414/live2d-to-agent). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.