Generate a video on emaki

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

With no annotations, the description carries the full burden and does so well: it discloses cost ('Runs on your emaki credits, the same price as on the website'), latency ('Video takes minutes'), sound-in-same-pass behavior, and the async run-id return contract. These are non-obvious behaviors an agent must plan around.

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, front-loaded with purpose, then default model, then cost, then async contract. Every sentence earns its place with no repetition of schema fields.

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 9 parameters, no output schema, and no annotations, the description fills the critical gaps: what is returned (a run id), how to continue (check_status), cost implications, and expected latency. An agent has everything needed to invoke and follow up correctly.

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 baseline is 3, but the description adds cross-parameter meaning the schema does not: the Seedance 2.5 default, the 4–30s range coupling, and the fact that image_url switches the tool into image-to-video mode. That extra interpretive context lifts it above baseline.

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 video clip from a text prompt on emaki.ai') and immediately distinguishes the two modes: text-to-video vs image-to-video via image_url. It also names the default model and routes the agent to the check_status sibling.

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 the two usage modes and the asynchronous default ('returns a run id to poll with check_status'), plus the wait flag as the blocking alternative. It lacks any when-not-to-use guidance against siblings like generate_image, so it stops short of a 5.

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