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

Annotations already declare readOnlyHint=true, so the description need not repeat that. It adds useful context beyond annotations: the output is intended as input for census_query_data and census_compare_geographies, and it warns that not all datasets support all geography levels. This enriches the behavioral profile without contradicting any annotation.

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?

Three sentences with no filler. The main purpose is front-loaded, followed by usage context and a practical note about output reusability. Every sentence earns its place, and the description is well-structured for quick scanning.

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?

Given the tool's simplicity, the presence of an output schema, and annotations covering read-only behavior, the description is complete. It explains when to use it, what it returns (geography levels and required parent geographies), and how to use the result. No critical information is missing.

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%: both year and dataset have clear descriptions, including the default behavior for year and the pointer to census_list_datasets for valid dataset codes. The tool description does not add any additional parameter-level meaning beyond what the schema already provides, so a baseline 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 states a specific verb ('List') and resource ('geography levels available for a given Census dataset and year'), and immediately clarifies the tool's role as a pre-query validation step. It distinguishes itself from siblings like census_query_data by emphasizing it returns valid inputs for those tools.

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?

Explicitly instructs 'Use before querying to confirm that the target geography level exists' and gives a concrete reason (ACS1 omits sub-state levels). It also notes the returned values are valid inputs to other tools, effectively stating when to use it and how the output connects to follow-up calls.

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