start_video

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

Annotations already establish that this is a non-read-only, open-world, non-destructive operation, so the description only needs to add context. It usefully discloses the asynchronous contract (returns immediately, no waiting), but omits the paid/cost-gated nature of the call and the fact that confirm_cost=false merely quotes a price, which is the most consequential behavior here.

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 front-loaded sentence with the async guarantee parenthesized for emphasis. Every clause earns its place and nothing is padded.

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?

An output schema exists, so return values need no explanation, and the async nature is covered. However, for a job-starting tool sitting next to get_video_status, the description should say what to do after receiving job_id and note the cost-confirmation requirement, both of which are left unstated.

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 schema already explains all seven parameters including confirm_cost's gating semantics. The description adds no parameter-level meaning beyond that, which is the expected baseline when the schema does the work.

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 ('Start a video generation job') plus the immediate return ('job_id'), which cleanly separates it from the polling sibling get_video_status. It stops short of naming that sibling, so the differentiation is inferred 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?

'No waiting' implies this is the kickoff call and that status is checked elsewhere, but the description never names get_video_status as the follow-up. It also gives no guidance on when to use this versus generate_image or when the cost-confirmation step applies.

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