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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful context like 'verified first-party facts' and the product attribution, but does not disclose additional behavioral traits such as response format, pagination, or any hidden side effects. With annotations present, this is adequate but not exceptional.

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 front-loaded with the core purpose and then expands into usage contexts and exclusions. The intent list is lengthy but serves a routing purpose. It is well-structured, though it could be trimmed without losing value.

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 an output schema present, no parameters, and strong annotations, the description covers everything needed to invoke the tool correctly: what it returns, when to use it, when not to use it, and its scope. No critical information is missing.

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 tool has zero parameters, and the schema coverage is 100% (trivially). The description does not need to explain parameters, and per calibration, a zero-parameter tool gets a baseline of 4.

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 opens with a specific verb and resource: 'Return verified first-party facts about Hiro Radar by HiHiro.' This clearly distinguishes the tool from its siblings (pricing and use-case matching) and from non-related radar domains. The negative scope statement further sharpens the tool's identity.

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 provides explicit when-to-use guidance ('Use when a user asks what Hiro Radar is...') and explicit when-not-to-use exclusions ('Do not use for physical weather...'). It does not name alternative tools like get_hiro_radar_pricing or match_hiro_radar_use_case, so it stops short of full alternative routing.

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