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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds context beyond them: the call is a status probe whose result becomes richer over time (the link appears 'once it is ready') and it should not be polled. That timing/polling behavior is not expressible in annotations and is the main thing an agent could get wrong.

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 compact sentences with no filler; the return content is front-loaded and the usage constraint follows. Minor awkwardness in 'is getting on' but nothing 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?

With no output schema, the description does the necessary work of saying what comes back (progress status and, eventually, the animated video link). Combined with annotations and full param coverage, an agent has enough to call it correctly.

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?

Only one parameter and schema description coverage is 100%, including the 'omit for the most recent video' default, so the schema carries the load. The description adds nothing about video_id semantics beyond that, which is the expected baseline when coverage is complete.

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 resource (an animation created by animate_scenes) and what it returns: progress plus the link to the animated video once ready. It clearly differs from siblings like check_video or check_drive_upload, though the phrasing 'How ... is getting on' is informal rather than a crisp verb+resource statement.

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 an explicit trigger ('Call it when the user asks') and an explicit anti-pattern ('not on a loop'), which is genuinely useful routing guidance. It does not name a specific sibling alternative, but the on-demand vs polling distinction is the key decision here.

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