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

With no annotations the description carries the full burden, and it does disclose several traits: the tool is paid ($0.002), it works from sitemap/robots.txt plus a bounded 1-hop crawl, and it returns a JSON list. Not covered are failure behavior when no sitemap exists, rate limiting, or whether the 1-hop crawl respects robots directives.

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, zero filler, and the cost and mechanism lead. The comparison to webcap_extract is placed last where it belongs as a routing hint.

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 two-parameter, non-destructive discovery tool with no output schema, the description tells the agent the source of URLs, the crawl depth, the output format, and the cost. Missing only edge-case behavior (empty sitemap, redirect handling) that would push it to 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%, including the url format and the maxUrls range/default, so the schema already documents both parameters fully. The description adds no syntax or format detail beyond it, which makes the baseline 3 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?

States a specific verb (discover) and resource (a site's URLs) plus the exact mechanism (sitemap, robots.txt, 1-hop same-host crawl) and the return shape (JSON list). It explicitly contrasts itself with webcap_extract, so an agent can distinguish it from siblings without reading schemas.

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?

Gives a clear selection signal: it is 'cheaper than crawling each page with webcap_extract,' which tells the agent to prefer this for URL enumeration over page-level extraction. It does not state when NOT to use it (e.g. dynamic sites without sitemaps) or any preconditions like host reachability.

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