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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description goes beyond them by disclosing the credit cost (2 credits), the fact that crawling is remote/open-world, and that the sample of links tested is capped, which materially affects what results the agent will see.

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, no filler, with the operation and cost front-loaded ahead of the constraint detail. Every clause carries information an agent needs before calling.

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 no output schema, the description usefully states the return shape (broken links plus HTTP status) and the sampling limit, which is enough to set expectations. It is slightly thin on crawl scope (single page vs. site-wide) and on the api_key parameter, but nothing blocking for a simple 3-parameter read-only tool.

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 0%, so the description must carry the load. It does well on max_links, giving the default (25) and hard ceiling (50), and 'crawl a page' implies the url parameter's meaning. The api_key parameter receives no explanation, though it is conventional, so the compensation is partial rather than complete.

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 uses a specific verb ('Crawl a page and test its links') and names the concrete output ('every broken link with HTTP status'), so the agent knows exactly what the tool produces. It does not explicitly differentiate itself from the sibling scan_website, which is the only reason it falls 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 rather than stated: the tool is clearly for link validation, and the credit cost hints at when it is worth invoking. However, there is no explicit when-to-use guidance and no mention of when to prefer scan_website or check_page_seo instead, leaving the agent to infer the boundary.

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