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

Annotations already declare readOnly, non-destructive, closed-world, so the safety profile is covered. The description adds real behavioral value beyond that: result ordering is cheapest-first, output includes per-call coin cost, and it encodes a default-selection policy with escalation rules. It stops short of describing result volume or exact fields, so a 4 rather than 5.

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?

Two sentences, front-loaded with what the tool returns, followed by when to call it and the default policy. Every clause carries decision-relevant information; 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 no-parameter, read-only listing tool with annotations covering safety, the description supplies everything an agent needs: what comes back, how it is ordered, and how to act on the results. No output schema exists, and the description still communicates the relevant return content.

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 of 4 applies. The model names mentioned (nano_banana_2, seedance_2_mini) serve as downstream defaults rather than parameter documentation, which is appropriate here.

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 ('List Dora generation models') plus the ordering and payload ('cheapest-first, with per-call coin cost'). This is clearly distinct from the sibling generators/checker, so an agent can route without opening any schema.

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 explicit trigger conditions: user asks what models exist, cost matters, or a model name needs verification. It also supplies when-not guidance by naming the defaults (nano_banana_2 / seedance_2_mini) and the only conditions to step up — explicit quality, face preservation, or audio requests.

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