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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, which cover the main behavioral traits. The description adds that the tool returns game counts per genre, but does not elaborate on other behavioral aspects like rate limits or response structure. The description is consistent with annotations and adds minor context.

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 a single, well-structured sentence that front-loads the main action and includes concrete examples. Every word contributes value, with no wasted 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?

Given the simplicity of the tool (no required parameters, no output schema), the description provides sufficient context: what it lists, from where, and what additional info is included. It could be slightly more complete by describing the return format (e.g., a list of objects), but the examples partially address that. No output schema exists, so the description carries the burden adequately.

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 single parameter _apiKey is fully described in the input schema (100% coverage), so the description adds no additional meaning. Baseline score of 3 applies because the schema already handles parameter documentation adequately.

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 uses a specific verb ('List') and clearly identifies the resource ('all video game genres in the RAWG database') and additional detail ('with game counts per genre'), with concrete examples. It distinguishes this tool from sibling tools like list_platforms, which lists a different resource.

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 implicitly indicates when to use the tool (when listing genres), but provides no explicit guidance on when not to use it or alternatives. For a simple listing tool this is adequate, but it does not reach the standard of explicitly stating use cases or exclusions.

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