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

Annotations already declare readOnly and non-destructive behavior, so the bar is lower. The description adds valuable behavioral details beyond annotations: dotted/undotted input normalization, canonical display output, and gender/cause-of-death restriction flags. There is no contradiction with 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 compact, front-loaded with the core purpose, and uses bullets efficiently. Every sentence contributes functional guidance without redundancy or filler.

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 single-parameter lookup tool with a rich input schema and an output schema, the description provides all necessary context: input forms, return value, example, and additional flags. Nothing critical is missing for an agent to invoke 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?

Schema coverage is 100% and the schema description already explains accepted forms with examples. The description reinforces dotted/undotted acceptance but does not materially add meaning beyond the schema, so the baseline 3 is appropriate.

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 action ('Look up a specific CID-10 code'), the exact resource (CID-10), and the output (Portuguese name), with a concrete example. It clearly differentiates this lookup tool from broad search or chapter-level tools in the sibling list.

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 'Use this tool to' bullets give clear context: resolving a code, confirming existence, and retrieving restriction flags. It does not explicitly name alternatives or exclusions (e.g., 'use cid10_search for free-text queries'), but the intended use is well implied.

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