kling_extend_video

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only mentions that the tool 'extend[s] an existing video with additional content' and returns a task ID and video info. It does not disclose whether the operation is destructive to the original video, any authentication requirements, rate limits, or if the extension is asynchronous (likely given sibling kling_get_task). This is insufficient for a mutation tool.

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?

The description is concise with three short paragraphs: action/outcome, usage cases, and return value. Every sentence serves a purpose; no fluff. However, the return information could be integrated more naturally.

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?

Given the tool has 7 parameters, 2 required, and an output schema (not shown but noted), the description provides the core usage context but lacks details on the process (e.g., asynchronous nature, polling for results). The return statement is vague ('Task ID and the extended video information') and relies on the output schema for specifics, which is acceptable but not ideal.

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 baseline is 3. The description adds some contextual value for the 'prompt' parameter by saying 'Describe the continuation of motion and new content,' but overall does not significantly enhance understanding beyond the schema's parameter descriptions.

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 clearly states the tool extends an existing video, using specific verb 'extend' and resource 'video'. It distinguishes from sibling tools like kling_generate_video which create new videos, and kling_get_task which checks status.

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?

The description provides three explicit use cases in a bullet list: video too short, continuing story, building longer piece by piece. This gives clear guidance on when to use the tool, though it does not explicitly state when not to use or compare with alternatives.

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