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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower. The description adds real value by disclosing the content of each returned item and the intended use of the url, which is essential given there is no output schema. It does not mention pagination or auth, so not 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 dense sentence with the purpose front-loaded, followed by the alternative and return-shape detail plus the endpoint. Nothing is wasted, though the parenthetical packing makes it slightly harder to scan than ideal.

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 usefully compensates by describing the returned fields (url, cover, length). Auth context (email) lives in the schema. For a simple list tool this is nearly complete, missing only pagination/volume expectations.

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 both parameters (mine, email) are already documented in the schema and the baseline is 3. The description reinforces the meaning of mine:true but adds no syntax or format detail beyond what the schema provides.

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 (list) and resource (Kling's ready-made motion videos), and ties it to the consumer tool kling_motion_control, so the agent can distinguish it from the many other kling_list_* siblings. The description also clarifies what each returned item is (a motion video with a url, cover, and length).

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 names the related tool (kling_motion_control) and explains the returned url is meant to be passed as motionUrl, which implies when to reach for this tool. It also flags the mine:true variant for the user's own motions. It stops short of explicitly stating 'call this before kling_motion_control' or any exclusions.

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