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

Annotations only say this is a non-destructive, non-idempotent mutation. The description goes well beyond that by disclosing the two expiry windows (6 hours vs 30 days), the Made with UGC Fans badge on showcase pages, that it is free, and that anyone holding the link can view the file without signing in. Public-exposure and lifetime details are exactly what an agent needs before sharing a file.

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?

Four short sentences, front-loaded with the core action before the mode details. Efficient overall, though the final sentence partially restates the opening's 'opens for anyone who holds it' point.

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 should ideally say it returns a URL, which it does not. Otherwise it fully covers behavior, lifetime, and both parameters for this simple two-parameter 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 100%, so the baseline is 3. The description earns above baseline by giving the `kind` choice real meaning - link = 6-hour direct file access, showcase = 30-day badged page - which the enum description alone does not convey.

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 and resource: 'Makes a link that opens one file of the library'. The purpose is unambiguous and the sharing scope is spelled out. It does not distinguish itself from any sibling tool, but the sibling set is mostly film/render operations so collision risk is low.

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 through the link-vs-showcase durations rather than stated: an agent can infer 'use showcase for a longer-lived page' but there is no explicit when-to-use or when-not-to-use guidance, nor any named alternative. Adequate but leaves the selection rationale to inference.

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