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

With readOnlyHint=true, the description adds useful behavioral context beyond annotations: it mentions the update cadence ('Updates: on source cadence') and the Gold-tier requirement for history data. These are non-obvious behaviors not captured by the 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?

The description is compact and front-loaded. The first sentence delivers the core output, the second gives use cases, and the third covers updates. No filler or redundant repetition of schema details.

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?

Despite no output schema, the description lists the key return fields (composite_score, component_scores, drivers, coverage) and clearly states the county-level scope. It could be slightly more explicit about whether all counties are returned, and which six layers are used, but it is largely complete for a read-only data 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?

Schema coverage is 100%, and the schema itself fully documents the optional 'days' parameter, including tier requirement and fallback behavior. The main description does not add parameter meaning beyond what the schema already provides, so the baseline of 3 applies.

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 uses a specific verb ('Returns') with a precise resource: a 0-100 county-level concentration score for AI-ready infrastructure and data-center capacity. It also names the output components and the composite data source, making the tool's purpose unmistakable and distinct from sibling 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?

The description gives explicit when-to-use guidance: 'Call when the user asks where AI-ready infrastructure or data-center capacity is concentrated...' It lacks explicit when-not-to-use statements or named alternatives, so it falls just 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.