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

With no annotations provided, the description carries the full behavioral burden and does well by disclosing that sensors are live and public, what each result contains, that a signed receipt is returned, and that calls cost $0.03 with the first 3 priced calls free. It still omits auth/payment mechanics and failure behavior when no sensors match or max_km excludes everything.

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 sentences, front-loaded with the core behavior and followed by essential pricing. Every clause earns its place by covering either returned data or cost.

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 is largely complete for a 4-parameter tool with full schema coverage and no output schema: it explains the return contents at a high level and covers pricing. Missing details about error cases, max_km filtering behavior, and the signing/payment flow keep it from a 5.

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 description coverage is 100%, so the schema already documents latitude, longitude, layers, and max_km. The description adds the useful return-shape semantic of 'one per layer asked for' and expands layer examples, but it does not add meaning for max_km or refine the coordinate parameters.

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 a specific resource and scope: nearest live public sensors to a point, one per requested layer, with readings, distance, source, and a signed receipt. It does not explicitly distinguish itself from siblings such as weather_now or air_quality_now, so it stops short of a 5.

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?

Usage is implied by the layer-based sensor retrieval and by the cost/free-call information, but the description never states when to use this tool instead of weather_now, air_quality_now, or other siblings. There are no explicit alternatives or exclusions.

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