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

Annotations only declare readOnlyHint=false, openWorldHint=true, destructiveHint=false. The description adds critical traits annotations cannot convey: ~90s latency, client timeout risk, a returned link, and the billing consequence of retrying after an apparent failure.

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?

Front-loaded with what it does and what it returns, then latency, then the alternative, then failure guidance. Dense and purposeful, though the all-caps emphasis and multi-clause failure instruction push it slightly past what a single read needs.

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 states the return value (a link to the finished video), and it covers the operational hazards (latency, timeouts, double-billing on retry) an agent needs to call and handle this safely. Nothing material 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?

Schema coverage is 100% with only 2 parameters, so the schema fully documents 'prompt' and the aspect_ratio enum. The description adds no syntax or format 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?

States a specific verb+resource ('Generate a short video') and names the exact model (Kling 2.5 Turbo Pro) plus the motion character it produces. This clearly differentiates it from the sibling generate_video_veo without needing to open either schema.

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?

Explicitly routes the agent: use this for cinematic motion, but if the user needs speed, generate_video_veo is about 60s. It also prescribes pre-call behavior (warn the user about ~90s) and failure handling (do not silently retry), leaving nothing to inference.

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