list_categories

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

No annotations are provided, so the description carries the burden of disclosure. It clearly states that the tool lists all unique categories and includes counts, which implies a read-only operation with no side effects. However, it does not mention ordering, pagination, or any potential limitations, though these are likely not relevant for such a simple tool.

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, concise sentence that front-loads the action and resource. It contains no filler and every word contributes meaning, earning a perfect score.

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 tool with no parameters and no output schema, this description is complete. It conveys the tool's purpose, the nature of its output (unique categories with counts), and implies its read-only behavior. There is no missing information that would prevent an agent from using it correctly.

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 input schema has zero parameters, and schema coverage is effectively 100%. According to the guideline, a baseline of 4 is appropriate when no parameters exist, as there is no parameter information for the description to add beyond the 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?

The description clearly states the verb 'List', the resource 'unique skill categories', and the scope 'all' with the additional detail of 'skill counts'. This clearly distinguishes it from sibling tools like list_skills, which list skills rather than categories.

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 implies usage: when you need to see skill categories and their counts, use this tool. However, it does not explicitly contrast with alternatives like list_skills or search_skills, leaving the decision to the agent's inference from sibling names.

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