Discord MCP Server

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 mentions the tool downloads and returns an MCP file reference, but doesn't cover critical aspects like authentication needs, rate limits, file size constraints, error handling, or whether it performs network operations that might be slow or fail. This leaves significant gaps for a download operation.

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 front-loads the core purpose ('Download a Discord attachment') and specifies the return type. There is no wasted verbiage, making it highly concise and well-structured for quick understanding.

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 download operation with network implications) and the absence of annotations and output schema, the description is incomplete. It doesn't explain what an 'MCP file reference' entails, potential errors, or behavioral traits like caching or file handling. For a tool with no structured safety or output info, more context is needed.

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?

The input schema has 100% description coverage, clearly documenting the 'url' parameter as a Discord CDN URL. The description adds no additional parameter semantics beyond what the schema provides, such as URL format examples or validation rules. With high schema coverage, a baseline score of 3 is appropriate as the schema does the heavy lifting.

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 action ('Download') and resource ('Discord attachment'), specifying it returns an 'MCP file reference'. However, it doesn't explicitly differentiate from sibling tools like 'discord_list_attachments' or 'discord_get_message' which might also handle attachments indirectly, making it clear but not fully sibling-distinctive.

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?

No guidance is provided on when to use this tool versus alternatives. For example, it doesn't mention if this is for downloading attachments from messages retrieved via 'discord_get_message' or 'discord_list_attachments', or if there are prerequisites like having a valid Discord CDN URL. The description lacks context for usage decisions.

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