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

With no annotations, the description carries the burden and does fairly well: it discloses the payment requirement and price ($0.001 USDC on Base via x402), the recursion ceiling, and the deduplication behavior. It omits failure modes, rate limits, and whether the URL must be reachable/non-authenticated, so it stops short of full disclosure.

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?

One dense sentence front-loads the core action and scope, followed by a short cost sentence. Nothing is wasted, but the action sentence packs several clauses together without structural separation, which slightly reduces scanability.

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?

There is no output schema and no annotations, so the description usefully enumerates the returned fields (loc, lastmod, changefreq, priority) and the cost. The remaining gap is the undocumented limit parameter and error behavior, but for a 1-required-param fetcher it is largely complete.

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 compensate. It clarifies that url targets a public sitemap and that depth is capped (matching max_depth's max of 2), but the limit parameter and its 2000 maximum are never explained, leaving one of three parameters semantically bare.

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?

Specific verb chain (fetch, parse, recursively expand, return) applied to a precise resource (public sitemap.xml or sitemap index). Scope constraints (two levels of recursion, deduplication) and the returned fields are stated, so an agent can distinguish it at a glance from sibling HTML-scraping tools such as html-links or extract-article.

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?

It implies the audience and precondition ("for crawlers and autonomous agents", "public sitemap"), which hints at when it applies, but it never names a competing sibling (e.g. webpage-links) or states when this tool is the wrong choice. Usage is implied rather than an explicit when/when-not.

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