Start here: what Hermoso can do and what it costs

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds further behavioral context: it is 'free' (costs no credits) and clarifies that the rendering tools route to server defaults when `model` is omitted. This goes beyond the annotation-derived safety and helps the agent plan resource usage.

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 pack all essential information without redundancy: what it does, when to call it, and a clarifying non-prerequisite statement. The key purpose is front-loaded, and every sentence earns its place.

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 parameterless, read-only probe, the description is fully sufficient. It enumerates the exact types of data returned, states that it is free, and clarifies that it is not needed before rendering. Together with the annotations, an agent has everything required to decide whether and when to invoke it.

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 has zero parameters, so the schema trivially covers 100% and there is nothing to explain. The baseline for 0 parameters is 4, and the description does not need to add parameter documentation; it instead focuses on the output contents, which is appropriate.

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 description opens with a strong verb-object pair ('Probe what this Hermoso account can do') and enumerates exactly what is returned: model ids, credit costs, aspect ratios, durations, recipe ids, and flags. It distinguishes itself from rendering tools by explicitly stating it is not a prerequisite, so an agent can tell it apart from generate_image, generate_video, and render_ad without opening their schemas.

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?

Provides explicit when-to-use guidance ('Call it when you need a specific model id, an exact cost, or a capability you are not sure of') and also states when it is NOT needed ('It is NOT a prerequisite for rendering'), naming the sibling tools that run without it. No ambiguity remains.

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