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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so safety is covered. The description adds value by specifying the return content (overall score, letter grade, category scores) and the 'no findings or prose' limitation, plus the efficiency angle ('cheapest useful call'). No contradictions with annotations.

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 two tight sentences that lead with the core value proposition ('cheapest useful call') and return details, then provide usage guidance. No filler or repetitive content.

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?

For a simple retrieval tool with one well-documented parameter, an output schema (indicated), and strong annotations, the description covers the essentials: what it returns, when to use, and how it differs from heavier options. It gives enough context for an agent to decide and invoke correctly.

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 input schema has 100% coverage and adequately describes the url parameter, including the bare domain handling. The description does not add parameter-specific information, but since the schema is complete, a baseline score of 3 is appropriate.

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 returns an overall score, letter grade, and every category score, with no findings or prose. It distinguishes from siblings like check_category (which would provide category details) and compare_websites by emphasizing it's the 'cheapest useful call' and a first step before going deeper.

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 explicitly lists use cases: comparing sites, when the user only wants a number, or as a first step before deciding which category to look into. It also hints at when not to use it ('with no findings or prose'), implying that for detailed findings one should use other tools, though it doesn't name them directly.

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