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

Annotations already declare the tool as read-only, idempotent, open-world, and non-destructive. The description adds useful behavioral context about the provider and return format (direct MP4 URLs), but it does not mention licensing, attribution, rate limits, or any limitation on results.

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?

The description is a single, front-loaded sentence with no wasted words. It efficiently communicates resource, return format, provider, and intended usage.

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?

Given annotations that cover safety and external-world behavior, plus complete schema descriptions and no output schema, the description provides enough context to call the tool correctly. It states the return format as direct MP4 URLs, though it could note whether results include metadata or attribution requirements.

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 input schema already documents all six parameters including query, count, provider, duration bounds, and orientation. The description adds no parameter-level meaning beyond what the schema provides, so the baseline of 3 is appropriate.

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 the resource (stock videos), the concrete return value (direct MP4 URLs), the provider (Pexels), and the intended use (<video> tags). It implicitly distinguishes from find_image by being about videos, but does not explicitly name that sibling or any other alternative.

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 phrase 'for <video> tags' gives an implied use case, so the agent can infer this is for obtaining stock video assets for HTML video elements. However, it does not explicitly say when to use this versus find_image or other resources, nor does it state exclusions.

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