List categories

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

With readOnlyHint and openWorldHint already declared, the description adds useful behavior beyond the annotations: this is a one-level category read, ids feed browse_category, costs are in $0.001 units, and failed calls are not billed. It does not describe return fields or pagination, but the safety profile is already covered by annotations.

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?

The description is front-loaded with purpose and usage, then presents platform-specific parameter support and cost behavior compactly. Every section helps the caller decide and invoke the tool; there is no redundant text.

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 read-only, open-world listing tool with no output schema, the description covers invocation sufficiently: platform selection, categoryId semantics, accepted platform parameters, and billing behavior. It lacks return-shape details such as category fields or pagination, which are the main remaining gap.

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 schema has high coverage for top-level parameters, but params is a generic additionalProperties object; the description compensates by listing which parameters each platform accepts and by explaining categoryId omission versus child retrieval. It still leaves region values/types and some requiredness details implicit, and the '* = required' note is not clearly reflected in the listed parameters.

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 states a specific resource and scope: one level of a marketplace's category tree, with top-level versus child behavior controlled by categoryId. It also distinguishes the output's role from browse_category by saying the ids feed that sibling, so an agent can identify which tool to use.

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?

It gives clear invocation guidance: omit params.categoryId for the top level and pass an id to get children. It also names browse_category as the downstream consumer, but it does not explicitly state when to choose browse_category instead or whether list_platforms should be called first.

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