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

Annotations already declare read-only, non-destructive, and idempotent behavior. The description adds value by disclosing the optional limit and the set of returned fields, which goes beyond the annotations. It does not describe edge cases like pagination or default when limit is omitted, but these are minor.

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 with no wasted words. It front-loads the primary action and then lists the returned attributes, which is efficient and easy to scan.

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 simple list tool with one optional parameter and an output schema (context signal), the description fully covers the necessary behavioral and return information. It could mention what happens when 'limit' is omitted, but the phrase 'up to optional limit' implies a cap, and the output schema handles return structure.

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 only a bare 'limit' number with no description (0% coverage). The description compensates by calling it 'optional' and explaining it limits the number of characters returned, providing semantics that the schema lacks. It does not specify a default or maximum, but the meaning is clear.

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 resource ('Studio Ghibli characters'), clearly distinguishing it from sibling tools like 'person' (which likely retrieves a single character). It also enumerates the returned fields, making the purpose unambiguous.

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 by stating it lists characters, but it does not explicitly contrast with alternatives like 'person' or mention when to choose this tool over other list/entity endpoints. Usage context is present but not directly stated.

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