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

The description discloses key behavioral traits beyond the annotations: it is asynchronous, returns a generation_id, and requires polling. It also mentions the starting cost. The annotations only indicate this is a write operation with open-world semantics, so the description adds meaningful behavioral context. It doesn't cover failure modes or rate limits, but the async handoff is the most critical behavior.

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 (two sentences) and front-loaded with the primary action. The async polling note is essential and placed right after. The cost mention ('from $0.50') is slightly extraneous but short and could be relevant for cost-sensitive agents. No padding or redundancy.

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 moderate complexity (3 params, one required, no output schema), the description covers the essential runtime contract: async generation and polling. It doesn't explain return values, but it points to get_generation. Authentication/credit requirements are not mentioned, but the cost hint partially covers that. Overall, an agent has enough to invoke and complete the workflow.

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 parameters already have clear descriptions. The tool description does not add any extra parameter detail beyond what the schema provides. It implies the prompt is the main input, but that's already explicit. Baseline 3 is appropriate because the schema does the heavy lifting.

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 core function: 'Turn a prompt into a video.' This specifies the verb, resource, and input type, distinguishing it from image-based tools like image_to_video. However, it does not explicitly differentiate it from the similar sibling ai_video_generator, so it lacks full sibling differentiation.

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 clear operational guidance: it explains the asynchronous flow, instructing the agent to call get_generation until status is 'completed.' This tells the user exactly how to consume the result. It doesn't explicitly mention when to choose this over alternatives, but the text-input basis and async pattern are strong implied usage signals.

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