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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: the rendering constraints (max 1920x1080 either orientation, 30fps, 60s) and that the call consumes no units.

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, front-loaded with the preset listing and followed by the service constraints. No wasted filler, though 'either way up' is slightly informal phrasing where a clearer constraint statement would read better.

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 zero-parameter lookup with an output schema present, the description need not explain return values and correctly focuses on enumerating presets and stating service limits. The remaining gap is the absence of any when-to-use/routing hint, but nothing an agent needs to invoke it correctly is missing.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate. Baseline 4 applies; the enumerated presets serve as content description rather than parameter semantics.

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 names a specific resource — the engine's frame presets (listing exact resolutions) and frame rates — so an agent can tell it is a reference/lookup service rather than a renderer like video_render or video_still. It is clear but does not explicitly distinguish itself from the similarly reference-oriented video_schema 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?

There is no statement of when to call this versus alternatives such as video_schema, video_render, or video_cost. The only hint of usage is 'Costs no units,' which implies it is safe/free to call but does not constitute routing guidance.

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