Create video card

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

With no annotations, the description carries the full burden. It discloses the critical input constraint (direct video URL) but does not mention error behavior, default playback options, or side effects. It does not contradict any annotations because none are provided.

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 concise sentences: the first states the primary purpose, the second adds the essential constraint. No redundant or filler text.

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 an 8-parameter tool with no annotations, the description is too thin. It does not explain behavior for `loop`, `muted`, `poster`, `subtitle`, `contextActions`, or what 'render' means in the output. The output schema may cover return values, but the interaction model and edge cases remain underspecified.

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 very low (13%), so the description must compensate. It adds meaningful semantics for `src` (must be direct mp4/webm file, not streaming page), but the other seven parameters rely on their names and the schema definition for `contextActions`. Partial compensation.

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 action ('Render a card') and the resource ('with an HTML video player for a short clip'). It distinguishes itself from sibling card tools by specifying video content and the direct URL requirement.

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 explicit when-not guidance: 'src must be a direct http(s) URL to a video file (mp4/webm), not a streaming platform page.' It implies short clip usage but does not explicitly compare with alternative sibling tools.

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