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

Adds real behavior beyond the annotations: cost per call, an account-level prerequisite that can block invocation, 1-3 minute latency, and the returned generation_id plus the polling cadence needed. Annotations only say it is a non-idempotent, non-destructive, open-world write; the description supplies the operational facts an agent actually needs.

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?

Three sentences, each carrying distinct payload: purpose plus cost and prerequisite, then clip-shaping options, then what is returned and how to poll. Front-loaded with the action and no filler.

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 5-parameter generative write tool, the description covers cost, eligibility, latency, return value and the exact polling recipe. An output schema exists so return-shape detail is not required, yet the description still names generation_id, which is the key needed to proceed.

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 explains loop, motion, pose_id, mascot_id and end_pose_id, including precedence rules. The description restates the end_pose_id/loop framing as 'pinned at both ends' but adds no syntax or constraints beyond what the schema provides; baseline 3 applies.

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 and output artifact: animates a pose or mascot into a short silent MP4 clip. The pose-vs-mascot subject choice is named up front, which cleanly separates it from create_pose and create_mascot.

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 concrete operating context: 5 credits, an account prerequisite (must have bought credits at least once), and an explicit follow-up loop naming check_generation with wait_seconds 50. It stops short of saying when NOT to use this instead of create_pose or create_mascot, so it misses the top band.

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