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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive). The description adds genuinely non-derivable facts: the paid-plan entitlement gate, the immediate availability of the link, and the default-fileType rule ('the first the work has'). Permission and rate-limit behavior remain unstated.

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?

Effectively one dense sentence that front-loads the value proposition (watermark-free link) before the format and readiness details. The parenthetical plan requirement and trailing route add density but no wasted sentences.

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?

There is no output schema, and the description compensates by characterising the return value as a direct link a nd by stating formats and immediate readiness. The one gap is the email parameter's multi-account condition, which is left entirely to the schema.

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 description coverage is 100%, so the schema already documents workId, email, and the fileType enum with its default. The description restates the format-to-media mapping but adds no syntax, validation, or defaulting detail beyond the schema, so the baseline 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 states precisely what is returned: a direct link to a result without the Kling watermark, keyed by workId, in a specific media format, with the HTTP endpoint (GET /assets/download) named. It is a noun phrase rather than an explicit verb+resource, but an agent can immediately tell this apart from kling_list_works or kling_get_task, which are cited only as sources of the workId rather than alternatives.

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?

It gives real preconditions: the workId comes from kling_get_task or kling_list_works, and watermark-free links require paid Kling plans. It also states the resource is 'Ready at once', implying no polling loop is needed. It stops short of explicitly saying when not to use it (e.g. free-plan users needing a watermarked download).

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