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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is conveyed. The description adds some context—'Updates: on source cadence' and the methodology behind the score—but does not disclose potential errors, rate limits, or how county selection works. It provides only modest value beyond the annotations.

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 two sentences plus a short update clause. It front-loads the core function, then lists output fields and usage triggers without redundancy. Every sentence carries useful information, and the structure is easy to scan.

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 description covers purpose, usage, output fields, and update cadence, and the schema handles the 'days' parameter. However, it claims 'for any of 3,222 US counties' but offers no county parameter or explanation of how the tool returns data for a specific county, which is a notable gap. The field list helps, but the missing county selection mechanism makes it incomplete.

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 single parameter 'days' is fully documented in the schema, including behavior (history series vs. snapshot) and tier requirements (Gold tier). The description does not add any parameter-specific meaning beyond the schema, so with 100% schema coverage, a baseline of 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 clearly specifies a unique function: returning a 0-100 childcare availability score for US counties, with a detailed list of output fields. The topic (childcare) is distinct from sibling tools, and the scope (3,222 counties) is explicit, making it easy to distinguish even without naming alternatives.

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 explicitly lists when to use this tool: when the user asks about childcare availability, childcare deserts, family-friendliness, or when making site selection, relocation, expansion, or benefits decisions. This is strong positive guidance, but it lacks any 'when not to use' or named alternatives, so it stops short of a 5.

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