Discord MCP Server

discord_send_message

Send messages to Discord channels with optional file attachments, text-to-speech, and reply functionality for automated communication.

Instructions

Send a message to a Discord channel, optionally with up to 10 files

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": {
      "channelId": "<channelId>"
    },
    "name": "discord_send_message"
  }
}

Input Schema

Name	Required	Description
`channelId`	Yes	The Discord channel ID
`content`	No	Message content (max 2000 characters)
`files`	No	Files to attach to the message
`tts`	No	Send as text-to-speech message
`replyTo`	No	Message ID to reply to

Schema Changelog

Changes observed during successful MCP inspections.

First observedAug 16, 2025

TDQS

C2.9/5.0

Behavior2/5

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

With no annotations provided, the description carries full burden but lacks critical behavioral details. It mentions file attachment limits but omits permissions needed, rate limits, message formatting options, error conditions, or what happens on success. For a write operation with no annotation coverage, this is insufficient.

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, efficient sentence that front-loads the core purpose and includes the key optional feature. There's no wasted verbiage or redundancy, making it easy to parse quickly.

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 write operation with 5 parameters, no annotations, and no output schema, the description is incomplete. It doesn't address behavioral aspects like authentication needs, side effects, or response format, leaving significant gaps for an agent to understand tool invocation fully.

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 parameters are well-documented in the schema. The description adds minimal value by noting the optional file attachment capability (up to 10 files), which aligns with the schema's maxItems constraint but doesn't provide additional semantic context beyond what's already in structured fields.

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

Purpose4/5

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

The description clearly states the action ('Send a message') and target resource ('to a Discord channel'), with the optional capability of including files. It distinguishes itself from siblings like discord_edit_message or discord_delete_message by focusing on message creation, though it doesn't explicitly contrast with all messaging-related tools.

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

Usage Guidelines2/5

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

The description provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., channel access), compare with discord_edit_message for updates, or indicate when file attachments are appropriate versus other methods.

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