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

Annotations already declare readOnly, idempotent and non-destructive, so the safety profile is covered. The description still adds real context the annotations do not: the ~50 s ceiling on wait:true, the 7-day job retention window, and the shape of the completed result including the image-block variant. It does not describe behavior for expired or failed jobs, which keeps it from a 5.

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 tight block with no filler; the result payload is front-loaded before the wait flag and retention note. The opening is a bare noun phrase rather than a verb clause, which slightly delays the 'this fetches a job' reading, but nothing is redundant.

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 takes on the burden of describing return values (mediaId, size, duration, download URL, image block) and adds retention and timeout facts an agent needs to call it correctly. Only error/expiry handling is left implicit.

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%, with the wait parameter already documented as 'Wait up to ~50 s for the job to finish.' The description repeats that same wait semantics and adds no format, default, or fallback guidance for jobid. Baseline 3 is appropriate when the schema carries the parameter documentation.

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 resource precisely (a job of any of the four creation types) and states that it returns status plus, once completed, the result fields. The trailing "GET /jobs/{jobid}" disambiguates it as a single-job fetch, implicitly separating it from vids_list_jobs. It falls short of a 5 only because it never explicitly contrasts itself with the list or media siblings.

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 rather than stated: the presence of a wait flag and the emphasis on 'once completed' signal that this is the polling tool for a job returned by a create call. There is no explicit 'use this instead of vids_list_jobs when you already have a jobid' and no guidance on what to do if a job has aged out.

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