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

Annotations already declare readOnlyHint=true and openWorldHint=false. The description adds valuable context beyond these by listing the exact outputs (percentile rank, band, rate per 100k, top cancer sites), specifying coverage of ~3,049 counties with state exclusions due to USCS suppression, and giving accepted input formats. This exceeds the basic annotation disclosure.

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, front-loaded with the tool's core purpose, and every sentence provides essential information (data source, outputs, input forms, coverage). It is efficiently structured without wasted words.

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?

With no output schema, the description compensates by clearly enumerating return fields (percentile rank, band, rate per 100k, top cancer sites). It also covers input format variations, data coverage limitations, and the source period, making the tool's behavior fully understandable in context.

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 description for the single 'county' parameter is complete (100% coverage), and the description enhances it with concrete examples of FIPS codes and 'County Name, ST' formats. While the schema covers the basics, the description's examples are highly useful for correct invocation, justifying a score above baseline.

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 states the tool provides an age-adjusted all-sites cancer incidence index for any US county, specifying the data source and return fields. It distinguishes itself from sibling tools like adw.county_mortality by explicitly focusing on cancer incidence, making its 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 gives clear context for when to use the tool (for cancer incidence data by county) and provides input format examples. However, it does not explicitly mention alternatives or exclusions (e.g., 'use county_mortality for mortality data'), so it falls short of full explicit guidance.

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