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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds real value beyond that: it discloses that results carry a download URL and that omitting class_id silently changes the data scope to the collection, which is non-obvious behavior worth flagging.

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?

A single compact sentence that front-loads the resource and file types, then the scope branch, then the output hint. No filler.

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 one-parameter read-only list tool with no output schema, the description covers scope branching and the download-URL return hint adequately. It stops short of mentioning ordering, pagination, or whether file types can be filtered, which are minor but real gaps.

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 0%, so the description carries the full burden for class_id — and it does, defining both the supplied case (files of a class) and the omitted case (collection-wide). Only the expected value format/validity of class_id is left unstated.

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?

States a specific verb (list) and resource (files of type PDF, Word, images) plus the scope in which they are returned. It is clear what the tool does, but it does not distinguish itself from related siblings such as list_images or share_file, so an agent must infer the boundary.

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 implicitly explains the two usage modes: pass class_id for a class's materials, omit it to get the collection. That is useful conditional guidance, but there is no explicit when-not or named alternative (e.g. list_images for image-only listings), so the agent must infer the rest.

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