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

Adds substantial context beyond the annotations: it discloses that validation inspects file content, gives concrete failure examples (MP3 masquerading as a master, non-square or sub-3000px cover), and states the side effect that a failing file is removed. The removal statement sits in tension with the declared destructiveHint=false, though deleting a just-rejected transient upload is arguably not destroying existing user data.

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?

Three sentences, front-loaded with the core behavior, and the readiness sentence earns its place by preventing confusion with check_readiness. Slightly dense in the middle sentence's example list, but nothing is wasted.

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?

No output schema exists, and the description still communicates the two outcomes (attach vs. refused-and-removed) well enough to call the tool correctly. It does not describe what is returned on success or cover the label-connection requirement for the artist parameter, but those gaps are minor for a single-purpose validation tool.

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 coverage is 67%, so upload_id carries no description and the description never references it by name or explains what it is. The 'file itself, not its name' remark is about content validation rather than parameter meaning, so it does not compensate for the undocumented required parameter. 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?

States a specific verb pair (check and attach) and resource (the uploaded file itself, not its name), and explicitly separates itself from the confusingly similar check_readiness by explaining readiness is a different, larger condition. An agent can distinguish this tool from its siblings without opening a schema.

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?

Gives clear workflow context: this runs on an already-uploaded file and only attaches it when it conforms, and it names check_readiness as the adjacent step that reports release readiness. It does not explicitly mention request_upload or say 'call this immediately after requesting an upload', so the when-to-use guidance is strong but not exhaustive.

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