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

Beyond the readOnly/idempotent annotations, the description discloses diacritic-insensitive matching, the V2008 Brazilian revision, the official CBCD/USP translation basis, and category/subcategory result scope. These are non-obvious behavioral traits that affect query formulation and result interpretation.

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 action, and organized into scannable bullets. Every sentence adds either a use case, a behavioral constraint, or an alternative-tool pointer, with no 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 search tool with an output schema and clear annotations, the description covers purpose, language, version, diacritics, result granularity, and the key alternative tool. Nothing needed for correct invocation is missing.

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%, so the baseline is 3. The description adds value by giving example Portuguese queries ('infarto', 'diabetes', 'tuberculose'), clarifying the query language, and explaining the categories/subcategories distinction that maps to the level parameter. It does not add much to max_results, but the schema already fully documents that.

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 opens with a specific verb and resource: 'Search the Brazilian CID-10 ... by Portuguese text,' and immediately distinguishes itself from the international ICD-11 tool by naming icd11_search. It also states the granularity (3-char categories and 4-char subcategories), making the tool's scope 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?

A dedicated 'Use this tool to' list defines concrete clinical, billing, and translation scenarios, and the final sentence explicitly routes international ICD-11 lookups to icd11_search. This gives an agent clear decision criteria for selecting this tool over the most likely sibling alternative.

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