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

Annotations declare a non-read-only, non-idempotent, open-world write, and the description meaningfully extends this: it is an async job ('A job, like kling_text_to_video'), it costs ~20 credits per 5s, defaults to kling-v1-6 with sound on for v3-0, and it hits POST /videos/image2video-elements. That is substantive operational context beyond the annotations, though polling/return handling is only implied.

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?

Four dense sentences with no filler, and the primary action is front-loaded before model constraints and cost. It is information-packed but every clause (model limits, cost, job semantics, endpoint) earns its place.

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?

For a 15-parameter, two-model, no-output-schema tool, the description covers the model matrix, defaults, cost, and async job nature. The main residual gap is that result retrieval (task polling via kling_get_task) is only hinted at by 'A job, like kling_text_to_video'.

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%, so the parameter bar is baseline 3, but the description adds cross-parameter constraints the schema does not: elements require kling-v3-0, element count is capped at 3 inputs total, and negative_prompt/aspect_ratio variants are tied to model choice. Some duration/model text duplicates the schema verbatim, keeping it short of a 5.

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: generating a video by combining images (image_0..3) with elements (element_1..3). The 'elements' mechanism distinguishes it from kling_image_to_video and kling_text_to_video, though those siblings are not named for direct routing. Purpose is clear but sibling differentiation is implied rather than explicit.

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?

Explains model-specific constraints (kling-v3-0 supports elements and 3-15s; kling-v1-6 is images-only, 5/10s) and cost, which implies when each model is appropriate. However, it never says when to pick this tool over kling_image_to_video, kling_omni_video, or kling_kolors_elements_image. Usage is inferable but not stated.

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