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

Annotations only say this is a non-read-only, non-destructive mutation; the description adds the details an agent actually needs: a real monetary cost of $1.00 per clip, an out-of-band card payment flow, an immediate non-blocking return with a video id, and a 30-90 second render window requiring polling.

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 load: what it does, what it costs and how it is paid, and what the agent must do next. The asynchronous lifecycle is front-loaded right after the capability statement, with 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 7-parameter paid mutation with no output schema, the description covers the critical unknowns: pricing, payment, latency, and the required polling loop. It leaves minor gaps, such as what happens to a charge on an ERROR result or where the finished video file is retrieved, which the agent must infer from get_video_status.

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 coverage is 100%, so the baseline is 3, but the description adds economic meaning to the duration and resolution parameters by pricing the default 5-second 540x960 clip explicitly, letting an agent reason about cost tradeoffs. It does not discuss seed, negative_prompt, or the image parameter, which the schema already documents well.

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?

Opens with a specific verb and resource ("Generate a short video from a text prompt") and immediately scopes the artifact (5-second 540x960 clip). It also distinguishes itself from the sibling tools by naming get_video_status as the follow-up rather than a competing generation path.

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 clear operational guidance: call this to create, then poll get_video_status until READY or ERROR, and note that no account is needed because payment is by card via MPP. It stops short of explicit exclusions (e.g. when to instead use list_videos to reuse an existing clip) but the create-then-poll routing is unambiguous.

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