line_send_flex_message

Send a rich Flex Message to a LINE user or group.

SERVERUnClick SOURCE@unclick/mcp-server

Medium RISK CLASS

Category Write

Parameters 43 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-malamutemayhem-unclick-mcp-server/line-send-flex-message.md

WHAT IT DOES

What line_send_flex_message does on UnClick

AI agents use line_send_flex_message to create or update resources in UnClick, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your UnClick environment.

Parameter	Type	Required	Description
`to`	string	Yes
`alt_text`	string	Yes	Fallback text shown in push notifications
`contents`	object	Yes	Flex Message container as JSON object or string
`channel_access_token`	string	—

Parameters from the server's own tool schema.

RISK

Why line_send_flex_message is rated Medium

An AI agent can call line_send_flex_message faster than any human can review: one bad instruction and it creates or modifies resources in UnClick by the hundred, each call as confident as the last.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs line_send_flex_message safely

PolicyLayer is an MCP gateway: it sits between your AI agents and UnClick, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For line_send_flex_message, this is the rule to start with:

line_send_flex_message Rate-limited

line_send_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": {
    "line_send_flex_message": {
      "limits": [
        {
          "counter": "line_send_flex_message_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect UnClick, apply this rule, and every line_send_flex_message call is checked against it from then on.

FAQ

Questions about line_send_flex_message

What does the line_send_flex_message tool do? +

Send a rich Flex Message to a LINE user or group. It is categorised as a Write tool in the UnClick MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

What parameters does line_send_flex_message accept? +

line_send_flex_message accepts 4 parameters: to, alt_text, contents, channel_access_token. Required: to, alt_text, contents. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on line_send_flex_message? +

Register the UnClick MCP server in PolicyLayer and add a rule for line_send_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 UnClick. Nothing to install.

What risk level is line_send_flex_message? +

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

Can I rate-limit line_send_flex_message? +

Yes. Add a rate_limit block to the line_send_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 line_send_flex_message completely? +

Set action: deny in the PolicyLayer policy for line_send_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 line_send_flex_message? +

line_send_flex_message is provided by the UnClick MCP server (@unclick/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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