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

Annotations already establish that the tool is read-only, idempotent, and non-destructive Mend. The description adds valuable behavioral context by specifying the exact output metrics and emphasizing the strict one-cancer/one-country constraint. There is no annotation contradiction, and the description goes beyond the schema by defining what the returned figures include.

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 two tight sentences with a clear lead-off ('Figures for ONE cancer type in one country'), a concise list of return metrics, and practical examples. Every element earns its place; there is no padding or repetition of schema details.

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 read-only lookup with three straightforward parameters, the description is nearly complete: it states scope, return metrics, and typical usage examples, and its safety profile is covered by annotations. It does not describe the output format, but since there is no output schema, the metric list largely fills that gap. Minor details like data year or default behavior are not critical given the siblings and schema.

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 description coverage is 100%, so each parameter is already documented well. The description adds little parameter-specific meaning beyond the schema; it reinforces the country+cancer selection pattern and provides examples, but does not compensate for anything missing because nothing is missing. A baseline score of 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 clearly identifies the tool's scope: figures for one cancer type in one country, and it lists the specific metrics returned (new cases, deaths, prevalence, rate, risk). It does not explicitly name sibling tools like globocan_country_profile or globocan_cancer_types, so it doesn't fully distinguish itself from them, but the 'ONE cancer type in one country' phrasing conveys the core purpose unambiguously.

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 explicitly states when to use the tool: when the question names both a cancer and a place, with concrete examples ('breast cancer cases in India'). It does not mention alternatives or exclusions, but the usage condition is clear enough for an agent to select this tool correctly over sibling lookup tools.

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