broadcast_flex_message · LINE Bot MCP Server MCP

WHAT IT DOES

What broadcast_flex_message does on LINE Bot MCP Server

AI agents use broadcast_flex_message to create or update resources in LINE Bot MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your LINE Bot MCP Server environment.

WHY IT NEEDS A POLICY

Why broadcast_flex_message needs a policy

This tool creates and sends messages at scale to all followers of a LINE Official Account. While not destructive (messages can be sent without permanent data loss) and not financial, it is a Write action that modifies the communication state to a large audience. The blast radius is high because misuse could result in spam, misinformation, or phishing attacks sent to potentially thousands of users.

From the tool's definition Tool name is 'broadcast_flex_message' and description states it 'Broadcast a highly customizable flex message via LINE to all users who have added your LINE Official Account.' The 'broadcast' capability to 'all users' represents mass creation/modification of…

Risk signalsBulk/mass operation — affects multiple targets

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

broadcast_flex_message Rate-limited

broadcast_flex_message stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "broadcast_flex_message": {
      "limits": [
        {
          "counter": "broadcast_flex_message_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches LINE Bot MCP Server, so you can run agents against it safely.

FAQ

Questions about broadcast_flex_message

What does the broadcast_flex_message tool do? +

Broadcast a highly customizable flex message via LINE to all users who have added your LINE Official Account. It is categorised as a Write tool in the LINE Bot MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on broadcast_flex_message? +

Register the LINE Bot MCP Server MCP server in PolicyLayer and add a rule for broadcast_flex_message: 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 LINE Bot MCP Server. Nothing to install.

What risk level is broadcast_flex_message? +

broadcast_flex_message is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit broadcast_flex_message? +

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

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

broadcast_flex_message is provided by the LINE Bot MCP Server MCP server (tndfame/mcp_management). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.