Discord MCP Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. While it mentions the optional file attachment capability, it fails to disclose critical behavioral traits such as rate limits, authentication requirements, error conditions (e.g., invalid channel ID), whether messages are persistent, or what happens if content exceeds 2000 characters (though schema covers this). For a write operation tool with zero annotation coverage, this is a significant gap.

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

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

The description is a single, efficient sentence that is front-loaded with the core purpose ('Send a message to a Discord channel') and adds a useful detail ('optionally with up to 10 files'). There is no wasted language or redundancy, making it highly concise and well-structured.

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

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

Given the tool's complexity (a write operation with 5 parameters, no annotations, and no output schema), the description is minimally adequate but incomplete. It covers the basic purpose and file attachment capability but lacks behavioral context (e.g., permissions, errors) and usage guidelines. The high schema coverage helps, but for a mutation tool without annotations, more disclosure would be beneficial.

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

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

Schema description coverage is 100%, so the schema already documents all 5 parameters thoroughly. The description adds minimal value beyond the schema by mentioning the optional file attachment with a quantity limit ('up to 10 files'), which is already implied in the schema's maxItems. No additional semantic context (e.g., channelId format, file types supported) is provided, so the baseline 3 is appropriate.

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

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

The description clearly states the specific action ('Send a message to a Discord channel') and resource ('Discord channel'), with additional functionality ('optionally with up to 10 files'). It distinguishes itself from sibling tools like discord_edit_message (edits existing messages) and discord_delete_message (removes messages) by focusing on message creation.

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

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., needing channel access), when to use discord_edit_message instead for updates, or how it differs from discord_create_dm for direct messages. The optional file attachment is noted but without context about limitations or alternatives.

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