LINE Bot MCP Server (SSE Support)

Overview Schema Source Related Servers Discussions Admin

broadcast_text_message

Send plain text messages to all followers of a LINE Official Account for announcements, updates, or general communication.

Instructions

Broadcast a simple text message via LINE to all users who have followed your LINE Official Account. Use this for sending plain text messages without formatting. Please be aware that this message will be sent to all users.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`message`	Yes

Implementation Reference

src/tools/broadcastTextMessage.ts:26-37 (handler)

The async handler that executes the broadcast message operation using the MessagingApiClient.

async ({ message }) => {
  try {
    const response = await this.client.broadcast({
      messages: [message as unknown as messagingApi.Message],
    });
    return createSuccessResponse(response);
  } catch (error) {
    return createErrorResponse(
      `Failed to broadcast message: ${error.message}`,
    );
  }
},

src/tools/broadcastTextMessage.ts:18-38 (registration)

Registration of the broadcast_text_message tool within the MCP server.

register(server: McpServer) {
  server.tool(
    "broadcast_text_message",
    "Broadcast a simple text message via LINE to all users who have followed your LINE Official Account. Use this for sending " +
      "plain text messages without formatting. Please be aware that this message will be sent to all users.",
    {
      message: textMessageSchema,
    },
    async ({ message }) => {
      try {
        const response = await this.client.broadcast({
          messages: [message as unknown as messagingApi.Message],
        });
        return createSuccessResponse(response);
      } catch (error) {
        return createErrorResponse(
          `Failed to broadcast message: ${error.message}`,
        );
      }
    },
  );

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.0.1-localMar 19, 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 full burden. It discloses the broadcast nature ('sent to all users') which is crucial behavioral context, but doesn't mention rate limits, authentication requirements, message delivery guarantees, or potential costs/quotas. For a broadcast tool with zero annotation coverage, this leaves significant behavioral gaps.

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

Conciseness4/5

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

The description is appropriately sized (3 sentences) and front-loaded with the core purpose. Every sentence adds value: first states the action, second specifies text-only limitation, third warns about broadcast scope. No wasted words, though it could be slightly more structured.

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

Completeness2/5

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

For a broadcast tool with no annotations, no output schema, and 0% schema description coverage, the description is incomplete. It doesn't cover error conditions, response format, rate limits, or authentication requirements. The warning about 'sent to all users' is helpful but insufficient for safe operation.

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 0%, but the description adds no parameter-specific information beyond what's implied by the tool name and purpose. The single parameter (message object with text field) is documented only in the schema. The description doesn't explain the message structure, text length constraints, or provide examples.

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 clearly states the specific action ('broadcast a simple text message via LINE'), the target resource ('all users who have followed your LINE Official Account'), and distinguishes it from siblings by specifying 'plain text messages without formatting' (unlike broadcast_flex_message or push_flex_message which likely involve formatting).

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

Usage Guidelines4/5

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

The description provides clear context for when to use this tool ('for sending plain text messages without formatting'), but doesn't explicitly state when NOT to use it or name specific alternatives (like push_text_message for targeted messages vs broadcast). It implies this is for mass communication to all followers.

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

Deploy Server