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

Annotations already declare readOnlyHint=true, and the description's 'Fetch/parse' is consistent with a read operation. The description adds the JSON output format, which is useful, but it doesn't disclose other behavioral traits such as rate limits, auth requirements, or handling of invalid sitemaps. With annotations present, this is adequate but not rich.

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 short sentences, front-loaded with the primary action and output. Every word earns its place—no filler, no repetition of schema or annotations. This is an example of efficient, well-structured prose.

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 read-only tool with two parameters and no output schema, the description covers the core purpose (fetch/parse sitemap to JSON) and use case (enumerate pages). It doesn't elaborate on return value structure, but the 'into JSON' statement is sufficient for this complexity level. Minor gap: no mention of size limits, but maxUrls in schema covers that.

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%, so the parameters (url and maxUrls) are already documented in the schema. The description does not add additional meaning beyond the schema, so it meets the baseline but provides no extra value for parameter understanding.

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 states a specific action ('Fetch/parse'), resource ('XML sitemap'), and output ('into JSON'), plus a use case ('Enumerate a site's pages'). This clearly distinguishes it from siblings like rss_parse (RSS not sitemap) and fetch_html (general fetching not parsing).

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 phrase 'Enumerate a site's pages' implies when to use this tool (when you need page lists from a sitemap), but it does not explicitly state alternatives or exclusions. There is no guidance on when not to use it, so it stops at implied usage rather than clear context.

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