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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description adds value beyond that: it flags that the operation is free, that authentication is required, that the download url is permanent, and that sharing information is returned only 'when you can manage it' — a conditional result shape an agent could not infer from structured fields.

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 front-loaded sentence listing the returned attributes, followed by a short cost/auth note. Dense but waste-free; only the fragment 'Free.' is slightly clipped in phrasing.

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 tool with full annotation coverage and no output schema, the description compensates by enumerating the returned fields and their conditional availability. Nothing critical for correct invocation is missing.

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?

There is a single parameter with 100% schema description coverage, and the schema already explains that the id comes from list_files or save_file. The description adds no format, validation, or fallback guidance for the id, so the baseline of 3 applies.

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 names the exact resource (a single library file) and enumerates what it returns — boundary, format, detail, visibility, access, permanent download url, and sharing info. That is specific enough to separate it from list_files and get_boundary, though it relies on the title's verb 'Get' rather than stating retrieval explicitly in the body.

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 only implied: fetch the details of one known file. The prerequisite ('Needs an API key or a connected account') is stated, but there is no explicit when-to-use versus list_files or update_file, and no exclusion conditions.

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