List covered counties

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

With no annotations provided, the description fully carries the transparency burden. It discloses that only counties with verified endpoints are returned, and mentions the approximate count (155). No side effects or auth requirements are needed for a read-only list 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?

Two concise sentences: first declares the main function, second explains the optional filter. No redundant information.

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 one optional parameter, no output schema, and no annotations, the description covers the tool's purpose, filtering, and scope. It could mention the return format (e.g., list of county names or IDs) but the core functionality is clear.

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 100%. The description adds value by clarifying that the 'state' parameter accepts both abbreviations and full names, and that omission lists all. This goes slightly beyond the schema's own description.

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 returns all counties in the UrbanKit Atlas with verified ArcGIS REST parcel endpoints. It uses a specific verb ('Returns') and distinguishes from siblings like 'find_county' and 'get_parcel_endpoint'.

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 usage instructions: pass a state abbreviation or name to filter, or omit to list all ~155 counties. It does not compare to sibling tools but implies when to use state filtering.

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