Look up the census tract for a coordinate

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

No annotations are provided, so the description must carry the burden of behavioral disclosure. It adds useful context such as 'Free, no API key' and the data source, and specifies the census year (2020). However, it does not disclose potential limitations like US-only coverage or behavior for coordinates outside any tract, which would be relevant for a geocoding tool.

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 only two sentences and front-loads the main purpose. Every piece of information ('2020 census tract', 'county and state', 'latitude/longitude', 'free', 'no API key', 'source') adds value without unnecessary verbosity.

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?

The tool is simple with only two parameters and no output schema. The description covers the core purpose, return content, and access constraints. It could be considered slightly incomplete for not mentioning that census tracts are US-only or what happens for points outside the US, but overall it provides enough context for a straightforward lookup tool.

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 already provides full descriptions for both parameters (latitude and longitude in decimal degrees, WGS84), so schema coverage is 100%. The description adds minimal semantic value beyond what the schema provides, only referring to 'a latitude/longitude point', which is adequate given the high schema coverage.

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 action ('Return') and the resource ('2020 census tract') along with additional context (county and state) and input (latitude/longitude). It effectively distinguishes itself from sibling tools like geocode_address (which likely goes from address to coordinates) and get_tract_demographics (which focuses on demographics for a given tract).

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 implies use when given a coordinate and needing the census tract, and notes it is free and requires no API key. It does not explicitly mention when not to use it or name alternatives, but the context and sibling tool list make the appropriate use case clear.

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