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

Beyond the readOnlyHint and openWorldHint annotations, the description adds meaningful behavioral context: it is SSRF-guarded, it recursively processes sitemap indexes in a bounded way, and it requires payment via USDC/USDT on Base through x402 with 3 free calls per wallet. This gives an agent useful operational expectations not present in the annotations.

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 compact and front-loaded: the first sentence states the core behavior and input variants, the second covers output fields, and the third covers safety and payment. Every sentence contributes necessary information without redundancy or fluff.

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 tool with 5 parameters and an output schema, the description covers the essential operational context: accepted URL forms, returned fields, bounded recursion, SSRF protection, and payment/free-tier mechanics. It does not specify exact pricing per call, but that is peripheral and the schema/output schema fill in the remaining structural details.

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 baseline is 3. The description enriches the overall call context (e.g., URL input variants, bounded recursion, payment model), but it does not add much parameter-level meaning beyond what the schema already states for url, wallet, max_urls, and x_payment. It is adequate but does not go beyond the schema's descriptions.

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 clearly identifies the tool's job with a specific verb and resource: 'Parse a sitemap into the real URL list.' It also details the accepted input variants (direct sitemap.xml, sitemapindex, site root), making the purpose unmistakable. It does not name sibling tools explicitly, but the function is still clearly differentiated by its sitemap-specific scope.

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 description gives clear context about when the tool applies: it handles direct sitemaps, indexes, and site-root discovery via robots.txt. However, it offers no explicit guidance on when to prefer this tool over siblings like web_crawl, robots_check, or feed_discover, nor does it state when NOT to use it. Usage is implied rather than explicitly routed.

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