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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds genuinely non-redundant context: flat pricing at $0.002 USDC on Base or Solana, the x402 X-PAYMENT header mechanism, the alternative prepaid credit key via 'Authorization: Bearer xs_...', and exclusion from the free trial. It stops short of describing pagination or response shape, so it is strong but not exhaustive.

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?

A single dense sentence front-loads the core action and scan scope, with payment/auth details relegated to trailing parentheticals. Nothing is wasted and an agent can parse purpose and cost without reading further.

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 three-parameter read-only tool with full schema coverage and no output schema, the description covers action, scale, payment, and auth sufficiently to invoke it correctly. The main omission is that it does not confirm what is returned (a flat URL list) nor mention any rate limits on repeated paid calls.

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 all three parameters are already documented in the schema, including the limit range 1-1000 and default 200. The description corroborates the 1000 cap but adds no syntax or behavioral detail for 'search' or the accepted URL formats beyond what the schema states. Baseline 3 applies when the schema carries the load.

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 and resource ('map a website'), the discovery sources (robots.txt sitemaps and on-page links), and the scale cap (up to 1000 URLs). It does not explicitly distinguish itself from the sibling crawl_site, which an agent can only infer from 'discover URLs' vs. crawling.

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?

Usage is implied by 'discover URLs on a domain', and the description warns that it is not available in the free trial, which is real routing signal. However, it never says when to pick this over crawl_site or search_extract, nor any preconditions on the target site (e.g., must be publicly reachable or have a sitemap).

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