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

Annotations already declare readOnlyHint=true and openWorldHint=false, but the description adds domain-specific reassurance that matters in a credit system — 'spends no credits and changes nothing in the user's account'. It also discloses that the quote is only valid for the exact settings supplied (resolution, duration, audio, attached media length), which is a real behavioral constraint the annotations do not carry. It omits failure behavior for an invalid model key or mode.

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 short sentences, the core purpose and the read-only guarantee are front-loaded, and the follow-on maxCredits linkage closes it out. Nothing is padded; even the 'creates nothing' clause earns its place in a credit-consuming product.

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?

There is no output schema, yet the description states what comes back — the credit price — which is the essential return information. It is slightly thin on the response shape (whether it is a bare number or an object) and on what happens when the supplied settings are invalid, but the nested inputs object and enum are addressed well enough for correct invocation.

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 only 40%, with 'model' and 'inputs' documented but mode, prompt and category left bare in the schema. The description compensates partially by naming the price-relevant fields (resolution, duration, audio, attached media length) and implying inputs must mirror the create call, but it never explains the role of mode, prompt or the category enum, so half the parameters remain uninterpreted.

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?

The first sentence gives a specific verb and resource — 'returns the credit price of one video, image or motion-control generation' — and scopes it to 'these exact settings'. It also explicitly separates itself from the create_* siblings by stating 'It creates nothing, spends no credits', so an agent can tell it is a quote/simulation step, not a generation step.

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?

The description supplies a concrete workflow: quote first, then 'the quoted credits can be passed as maxCredits to the create tool', which tells the agent exactly how this tool feeds the creation tools. It does not explicitly route away from the closest read sibling, get_credits, so the agent must infer on its own that get_credits is an account balance rather than a per-generation quote.

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