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

Goes well beyond the annotations (which only say not-read-only, not-destructive, closed-world) by disclosing link lifetime (one hour), privacy, the account requirement ('same HanoLab account'), cost behavior ('no credits are spent'), and a hard input limitation that would otherwise cause a failed call. This is exactly the behavioral context an agent cannot 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?

Three tight sentences with no filler: purpose first, then the user interaction step, then the account/cost/limitation constraints. Every sentence carries information the agent needs to act.

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 still covers the creation semantics, expiry, requirements, and constraints, and 'upload link' implies the return value. It could be slightly more explicit about what the call returns (URL only vs. a link plus handle) and whether the link expires even if unused, but nothing essential 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The description correctly frames all required information as user-side actions rather than arguments.

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 ('Create a private one-hour browser upload link') with the key qualifiers (private, one-hour) front-loaded, so the agent immediately knows what artifact this produces and how long it lasts.

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 the intended workflow ('Ask the user to open it, choose an audio file or MP4 and return here') plus an explicit limitation ('cannot read local paths or ChatGPT attachments directly'), which tells the agent when this tool is the right path. It does not name a sibling alternative or an exclusion case, so it falls short of a 5.

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