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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds value by enumerating exactly what is returned (name, size, type, expiry, download link) — meaningful given no output schema — and clarifies that expiry is exposed, hinting at expired-file behavior.

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?

One front-loaded sentence with the verb, resource, accepted inputs, and return fields. Nothing is padded and nothing is missing.

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?

With no output schema, the description correctly carries the return-value burden and covers the sole parameter's dual input form. Only minor gaps remain — behavior for an expired or unknown id — which matter little for a read-only lookup.

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 100% and the schema already explains that id may be a file id or download URL, so the description matches rather than extends it. The single-parameter surface keeps this adequate, but no extra meaning (format, validation, what happens on a bad id) is added.

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?

Specific verb (look up) plus resource (relayed file) and an enumerated field list, so the agent knows this is metadata retrieval rather than content retrieval. It never names read_file, the sibling that returns content, so the distinction is inferred from the field list rather than stated.

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?

Usage is implied: call it with an id or download URL from an upload tool to get metadata. There is no explicit when-to-use/when-not guidance and no routing to read_file for actual file contents, which is the most likely sibling confusion.

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