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

With no annotations provided, the description carries full responsibility for disclosing behaviors. It mentions that an api_key is required, implying authentication. However, the input schema marks api_key as optional, creating a contradiction. No other behaviors (e.g., rate limits, pagination, sort order) are disclosed.

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, front-loaded sentence with no redundant information. It immediately states the purpose and a key requirement. Every word 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?

Given the tool has no output schema, the description should hint at return values. It does not. The tool is simple (1 optional param) so minimal context might suffice, but the missing output details and lack of comparison to similar tools leave gaps. Adequate but not complete.

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?

Schema coverage is 100% for api_key. The description adds the claim that api_key is 'required', which semantically constrains usage beyond the schema's optional flag. However, this contradicts the schema, reducing its helpfulness. It does not describe parameter values or format.

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 tool returns top crypto categories by market cap, indicating the verb 'get' and the resource. It distinguishes itself from sibling 'trending_categories' by specifying the sorting criterion. However, the verb is implied rather than explicit, which slightly reduces clarity.

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 provides no guidance on when to use this tool versus alternatives like 'get_top' or 'trending_categories'. It only mentions an api_key requirement, but does not explain context, prerequisites, or exclusion criteria. No usage scenarios are described.

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