cdc_life_expectancy

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

Annotations declare readOnlyHint=true, so the safety profile is already covered. The description adds the important behavioral limitation that data only goes through 2018, which is critical for setting user expectations. It does not mention pagination or default limits, but the core limitation is 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 concise and well-structured: a single clear sentence stating the main function, a second listing valid values, and a third providing a temporal caveat and an alternative tool. Every sentence serves a purpose without redundancy.

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 straightforward lookup tool, the description covers the essential context: the source (U.S. life expectancy), the filters (race, sex), the time range, and a pointer to an alternative for newer data. The lack of an explicit return format is minor since the nature of the data is clear from the name and description.

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 input schema provides descriptions and enums for all 4 parameters, giving 100% coverage. The description lists the enum values for race and sex, but these are already in the schema, so it adds no new semantics beyond what the schema provides. Thus, 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 specifies the action ('Get'), the resource ('U.S. life expectancy at birth'), and the dimensions (race and sex) with a clear time range (1900–2018). It also distinguishes itself from sibling tools by explicitly mentioning cdc_mortality_rates as an alternative for more recent data.

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 explicit when-to-use guidance by noting data ends in 2018 and directing users to cdc_mortality_rates for more recent mortality trends. This is a clear, actionable alternative that helps an agent choose the right tool.

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