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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description builds on that by detailing what data is returned (fiber density, competition, speeds, etc.). It adds the 'herd-mentality' framing, giving context beyond a bare read operation. It does not describe return format or pagination, but with readOnlyHint covering the safety profile, this is sufficient.

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 three sentences, each earning its place: first defines what the tool returns, second explains the conceptual context, third gives input instructions. It is front-loaded with the core purpose and avoids redundancy, making it an efficient and well-structured description.

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 absence of an output schema, the description does a good job listing the key output dimensions (FCC locations, providers, fiber density, speeds) and explains why this data matters (herd-mentality). It could be more explicit about response structure or edge cases, but for a read-only lookup tool, it conveys the essential information.

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% (lat, lng, hex_id each described). The description adds meaningful context by specifying 'any US coordinate', the hex resolution (~0.46 km cells), and that hex_id is a direct alternative to lat/lng. This reinforces and extends the schema descriptions, justifying a score above baseline.

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's function: 'Res-8 hex intelligence (~0.46 km cells) for any US coordinate' with specific data dimensions (FCC locations, providers by technology, fiber density, competition, underserved status, speeds). It distinguishes from siblings by emphasizing the neighborhood scale and 'build-predictability grain', making it unique among area-level 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 implicitly indicates when to use this tool: when you need 'herd-mentality context' or 'build-predictability'. It also specifies input expected ('Give lat+lng, or an H3 res-8 hex_id directly'). It does not explicitly name alternatives or exclusions, but the context of neighborhood-level detail vs. area intelligence is clear.

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