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

The description adds substantial behavior beyond the annotations: gzip support, 512 KiB expanded input cap, 1000-entry cap, filtering and pagination behavior, non-charging for invalid XML and execution errors, charging for valid empty matches, and the $0.002 USDC x402 cost. These details are highly relevant for an agent deciding whether and how to invoke a paid, open-world read operation.

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 dense but well structured: purpose first, then capabilities and limits, then exclusions, then billing behavior, then intended workflow. Every sentence carries operational information an agent needs.

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 that an output schema exists, the description does not need to explain return values in detail, and it already states that results are structured URLs with source-reported dates. It also covers constraints, billing, exclusions, and intended usage, leaving no major operational gap.

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 coverage is 100%, so the parameter descriptions already carry most of the load. The description still adds useful semantics not present in the schema, notably gzip support, the 512 KiB expanded-input limit, and the 1000-entry cap, though it does not add much per-parameter detail beyond that.

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 verb and resource: read one public XML sitemap or sitemap index as structured URLs and source-reported dates. It also distinguishes this from crawling or following child sitemaps, so an agent can tell it apart from page-fetching siblings like extract.

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 explicitly says to use this to find which docs pages to read before calling /extract, and it states the negative boundary: it does not crawl pages or follow child sitemaps. This gives both when-to-use guidance and an explicit alternative workflow.

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