Discord MCP Server

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

With no annotations provided, the description carries full burden for behavioral disclosure. While it mentions scanning 'recent messages' and listing attachments, it doesn't specify important behavioral aspects like whether this is a read-only operation, how messages are selected (chronologically?), what format the results come in, whether there are rate limits, or what happens with large channels. The description is insufficient for a tool with 5 parameters and no annotation coverage.

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 states the core functionality without unnecessary words. It's appropriately sized for the tool's complexity and gets straight to the point with zero wasted text.

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?

For a tool with 5 parameters, no annotations, and no output schema, the description is inadequate. It doesn't explain what the tool returns (list format, what fields are included), doesn't mention important behavioral constraints, and provides minimal guidance on usage. The description should do more heavy lifting given the lack of structured metadata.

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 description mentions 'recent messages' which relates to the 'limit' parameter, and 'attachments' which relates to the filtering parameters. However, with 100% schema description coverage, all parameters are already documented in the schema. The description adds minimal value beyond what the schema provides, meeting the baseline score for high schema coverage.

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 ('List all attachments') and resource ('in a Discord channel from recent messages'), making the tool's purpose immediately understandable. However, it doesn't differentiate itself from sibling tools like 'discord_search_messages' or 'discord_get_message_history' that might also retrieve message content including attachments, missing an opportunity for clear sibling distinction.

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 like 'discord_search_messages' or 'discord_get_message_history' that could also retrieve attachments. It doesn't mention prerequisites, constraints, or typical use cases, leaving the agent to infer usage context from the tool name alone.

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