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

Annotations already declare the write/idempotency/open-world profile, and the description adds two things beyond them: the required scopes (demos:read, demos:write) and the fact that the result starts with exactly one title scene. It stops short of saying what is returned (e.g., the new video id) that an agent needs to chain into add_scene.

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?

Two sentences and a requirements line, front-loaded with the defining trait (blank, one title scene) before the alternative. No filler; every clause carries information.

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 non-destructive creation tool with no output schema, the description covers intent, alternatives, and auth, but omits the three input parameters entirely and says nothing about the return value an agent must use to continue building the video. Adequate to choose the tool, insufficient to call it confidently.

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 0% for all three parameters (title, aspect, themeId), so the description carries the full burden — yet it mentions none of them. 'One title scene' faintly hints that a title exists, but nothing explains aspect ratios, theme selection, or defaults, leaving an agent to infer from bare property names and an enum.

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 states precisely what is produced — a blank video containing one title scene — and how it is meant to be used (built by hand with add_scene). The verb 'create' lives only in the name/title, so the description itself is a sentence fragment, but the resource and scope are unambiguous and clearly separable from generate_video.

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?

It gives an explicit alternative with its selection condition: 'To make a video from a demo or a brief, use generate_video,' and names the follow-on tool for the manual path (add_scene). Both the when and the when-not are stated outright.

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