callout

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

No annotations are provided, so the description carries the full behavioral burden. It states that annotations are shown between timestamps and that the output path is returned, but it omits side effects such as whether the source is modified, default overwrite behavior, maximum item count, and ordering semantics.

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 concise and front-loaded: it names the action, gives examples, explains timed visibility, and notes the return value. No sentence is wasted.

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?

The schema is rich and fully documented, and the description states the return value. However, for a write/create operation with no annotations, it could do more to clarify side effects and distinguish this tool from nearby video-editing siblings.

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 schema already documents all parameters and item types in detail. The description reinforces the high-level annotation types and timestamp visibility, but adds little parameter-level meaning beyond the schema.

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 a specific verb and resource: annotate a video with timed boxes, text labels, and arrows. The examples make the behavior concrete, but it does not distinguish this tool from related siblings such as overlay or title_card.

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 examples of what can be annotated but does not explain when to use callout versus alternatives like overlay, title_card, or burn_subtitles. There are no explicit inclusion or exclusion conditions.

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