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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false, so the description is not carrying the safety burden alone. It still adds genuinely new behavior: the operation is asynchronous and must be polled via get_packaging_variants, it produces both an MP4 and a cover, and it is free (cost information the agent cannot get elsewhere).

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 short sentences, zero filler, with the action front-loaded and the follow-up polling step second. Every clause carries information the agent needs.

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 one-parameter async mutation with no output schema, the definition covers the key gaps: what it produces, that it is free, and how to detect completion. It stops short of saying what is returned at start (e.g. an export ID) or what the cover format is, which is a minor residual gap.

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 the single variantId parameter, so the schema adds nothing. The description only implicitly characterizes variantId as identifying a 'challenger variant' and points to get_packaging_variants as the place that likely supplies it, but it never states the ID format or that the variant must already exist.

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?

States a specific verb (starts an export) plus the exact resource scope: a challenger variant's own MP4 export and cover. That phrasing clearly separates it from siblings like export_clip and export_whole_video_zip, which target different resources.

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?

Gives explicit post-call guidance: poll get_packaging_variants until exportStatus is ready, which tells the agent this is asynchronous and what to do next. It does not explicitly say when not to use it (e.g. versus exporting a whole video), but the packaging-variant framing makes the scope reasonably unambiguous.

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