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

Annotations already declare readOnlyHint and idempotentHint, but the description adds valuable behavioral context: 'Each site is a real audit, so this takes several seconds per URL.' This warns about latency and conveys that the operation performs real work. It also explains that output is ranked with category gaps, which is beyond the 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 sentences, front-loaded with the core action and output, followed by use cases and a performance note. No filler or redundancy. Every sentence earns its place.

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 tool's complexity (multiple URLs, ranking, output schema exists), the description is complete: it states input scope (two to four sites), output behavior (ranked with category gaps), and performance characteristics (several seconds per URL). The output schema covers return value structure, so no further detail is needed.

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 schema provides 100% coverage for the single 'urls' parameter, already describing it as 'The sites to compare. Bare domains are fine.' The description reinforces the two-to-four site range but does not add new semantic details beyond the schema. With high schema coverage, the baseline is 3, and there is no additional value from the description.

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: 'Score two to four sites and return them ranked, with the category gaps between them.' It uses a specific verb ('score' and 'rank') and resource ('sites'), and the use cases ('how do I compare to my competitors' or 'which of these is better built') make the purpose unmistakable. This also distinguishes it from sibling audit_website, which likely handles a single site.

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: 'Use it for "how do I compare to my competitors" or "which of these is better built".' This is clear context, but it does not explicitly mention alternatives or when not to use it (e.g., for a single-site audit), which would warrant a 5. The sibling list suggests audit_website as an alternative, but the description doesn't reference it.

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