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

With no annotations, the description carries the full burden and does so richly: cost ('one video allowance, the dearest single action'), latency ('renders in one to two minutes'), output ('returns its public address'), UI behavior ('the product plays it under this tool's row'), and an account gate (paid plan). This is far beyond a bare restatement of the schema.

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?

Front-loaded with the core action and outcome before cost and prerequisites, with no filler sentences. It is dense and packs several facts into each sentence, which borders on crowded but every clause carries operational value.

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?

Covers cost, latency, resolution trade-off, output (returns a public address), account requirement, and pre-call confirmation. With no output schema present, the description supplies the return behavior an agent needs, leaving no material gap for a 5-parameter tool.

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 real meaning on top: it ties quality 'best' to 720p 'at several times the cost' and connects first_frame_url to the output address of generate_image. It also frames the prompt as motion/scene content, though it doesn't add per-parameter syntax the schema lacks.

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 resource ('Make one short clip ... from a description') and bounds output immediately (three to eight seconds, 480p/720p). It explicitly distinguishes itself from the sibling generate_image by describing how to feed that tool's output in via first_frame_url.

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 when-to-use context (generate a clip from a description, optionally animating an existing picture) and names the alternative source (a picture generate_image already made). It adds a concrete precondition ('confirm the description with the customer before calling it') and a hard gate ('Requires a paid Mentionry plan').

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