@zients/line-mcp-server

Multicast Text Message

multicast_text_message

Send a text message to up to 500 LINE users at once using their user IDs. Broadcast announcements or notifications to multiple recipients in a single API call.

Instructions

Send a text message to multiple LINE users at once (max 500 user IDs).

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "userIds": "<userIds>",
      "text": "<text>"
    },
    "name": "multicast_text_message"
  }
}

Input Schema

Name	Required	Description	Default
`text`	Yes	Message text to send
`userIds`	Yes	Array of User IDs to send to (1–500)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.1Sep 4, 2026

TDQS

A3.5/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It states a basic send action but offers no detail on side effects, error handling, delivery confirmation, or any other operational behavior. The only added constraint (max 500) merely repeats the schema's maxItems, adding no new behavioral context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, concise sentence that front-loads the core action and the key constraint. There is no wasted wording or unnecessary detail.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple two-parameter send tool with full schema coverage, the description is largely sufficient to convey the basic operation. However, it lacks explicit guidance on when to choose this over sibling tools and does not mention any return value or error behavior, leaving some contextual gaps for an agent deciding how to use it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so both parameters (text and userIds) are fully documented in the schema. The description adds no additional meaning beyond the schema; it only echoes the max 500 limit already present in maxItems. Therefore, a baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states the verb 'send', the resource 'text message', and the recipient scope 'multiple LINE users at once' with a specific cap of 500 user IDs. This clearly distinguishes it from push (single user) and broadcast (all users) tools, even though it doesn't name them explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'multiple LINE users at once' implies usage for a targeted group rather than a single user or entire audience, but it does not explicitly mention alternatives like push_text_message or broadcast_text_message, nor does it state when not to use this tool. The guidance is implied, not explicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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