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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new context: prices are live, no sign-in is required, the call is free, and the currency depends on access method (credits vs. US dollars for an API key).

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 purpose and kept to two compact sentences with no filler. The em-dash enumeration of categories is dense and slightly cryptic in places ("a model per version"), but every clause carries information about scope or cost.

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 carries the burden of indicating what comes back, and it does so at a high level by naming the units (credits or US dollars per API key). It stops short of describing the shape of the response (per-item vs. tiered pricing), which is the only notable gap for a zero-parameter read.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline for a parameterless schema applies. Nothing is stated that conflicts with the empty object schema.

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 ("what things cost on Wandy3D, live") and enumerates the priced categories: model per version, text to 3D, Low Poly, rig, crafts, files, and free-account allowances. It also distinguishes itself from get_credits by noting that tool covers the user's own balance.

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 parenthetical routes the agent to get_credits for the user's own balance, which is a real disambiguation against the closest sibling. What is missing is an explicit trigger such as "call before generating to estimate cost"; the when-to-use is implied by the content rather than stated.

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