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

Annotations already declare readOnlyHint=true, so the safety profile is known. The description adds behavioral context by specifying the composite methodology, the exact output fields, coverage of all US counties, and update cadence. This goes beyond the annotations without contradicting them.

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 and structured: it opens with the return value, lists composition and fields, gives use cases, and ends with update frequency. Each sentence serves a distinct purpose with no redundancy.

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 no output schema present, the description appropriately lists the returned fields. It covers the main purpose, output, coverage, use cases, and update behavior. The optional history parameter is fully documented in the schema, so the description need not repeat it.

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 only parameter `days` has a complete description in the schema (100% coverage), and the description does not add further parameter details. Per the rubric, baseline is 3 for high schema coverage, and nothing in the description enhances parameter semantics.

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 begins with a specific verb and resource: 'Returns a 0-100 broadband access score for all 3,222 US counties' with detailed field names. This clearly distinguishes it from sibling county-level tools (e.g., cancer, mortality) by focusing on broadband and connectivity.

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?

It explicitly states when to call: 'Call when the user asks about internet quality, connectivity gaps, or underserved markets, or when timing site selection, remote-hiring geography, or build-out decisions.' However, it does not mention when not to use it or name alternative tools, so it falls 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.