Compare ZIPs

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

Annotations already declare readOnlyHint=true, and the description adds valuable behavioral details: results are sorted descending, ZIPs with missing data are listed last, and values are ACS 5-year estimates. This goes beyond the annotations and helps the agent understand output ordering and data provenance.

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 yet information-dense. It front-loads the core purpose in one sentence, then efficiently documents parameters and behavioral details in a bullet-like list embedded in prose. Every sentence adds value, with no fluff or repetition.

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 an output schema present, the description need not explain return format, and it wisely covers the essential behavioral aspects: sorting, missing-data handling, and the metric enum. It is slightly less explicit about when to prefer this over sibling tools, but it is complete enough for an agent to use 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 0%, but the description fully compensates: it defines 'zips' as a list of 5-digit US ZIPs and provides the complete list of allowed values for 'metric'. Without this, the agent would have no idea what values are valid or what each parameter means.

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 starts with a specific verb ('Rank') and resource ('several ZIPs'), immediately distinguishing it from sibling tools that operate on single ZIPs or specific metrics. It also enumerates the exact metrics, leaving no ambiguity about what the tool does.

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 clearly indicates the tool is for comparing multiple ZIPs on a single metric, which provides strong contextual guidance. It does not explicitly name alternatives or exclusion criteria, but the sibling list and the phrase 'several ZIPs' imply when this tool is appropriate versus single-lookup tools.

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