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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: it is a paid capability with a specific cost, it validates the target and returns a canonical x402 handoff, and the actual payment/result exchange happens at a separate endpoint. This goes beyond what annotations provide.

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 with the most critical information (paid capability, cost, and what it does). Every sentence adds value, though the x402 handoff explanation is somewhat dense and could be clearer for an agent unfamiliar with the protocol.

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?

The description covers the tool's purpose, scope, payment model, and handoff flow. The output schema exists, so return values don't need to be explained. The only minor gap is that it doesn't explicitly state when to prefer this over extract_structured_data or link_map, but the single-page Markdown scope is clear enough.

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 schema already documents the url parameter as 'A publicly reachable HTTP or HTTPS page.' The description adds the requirement that the page be public and single, but doesn't add much beyond the schema. Baseline 3 is appropriate.

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 ('Fetches'), a resource ('one public page'), and the output ('main content as clean Markdown plus title, description, outbound links, and word count'). It also explicitly distinguishes itself from crawling and JavaScript rendering, which helps differentiate it from sibling tools like link_map and extract_structured_data.

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 explicitly says 'Single page only — no crawling or JavaScript rendering' and explains the x402 HTTP handoff flow. It also notes that no account or API key is required, which helps an agent decide when to use it. It doesn't name sibling alternatives explicitly, but the single-page scope and payment model provide clear usage context.

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