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

Goes well past the readOnlyHint/openWorldHint annotations by disclosing the paid x402 model: $0.005 USDC per call, and crucially that an unpaid call returns payment requirements rather than content. It also tells the agent exactly how to retry (X-PAYMENT or PAYMENT-SIGNATURE header, or params._meta['x402/payment']), which is behavior an agent could not infer from any structured field.

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?

Four short sentences ordered by importance: what it does, why use it, what it costs, and how to satisfy payment. No filler, and the payment gotcha is surfaced before the agent commits to a call.

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 one-parameter fetch tool with no output schema, the description covers purpose, return values (Markdown plus title), cost, and the full failure/retry path. There is nothing an agent needs in order to invoke it successfully that is left out.

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?

The single 'url' parameter is fully documented in the schema, so baseline is 3. The description adds meaning beyond the schema by revealing a payment channel via params._meta['x402/payment'] and the alternative header mechanisms, which is not represented anywhere in the input schema.

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 ('Fetch one public web page') plus the exact return shape ('clean Markdown plus title'). The word 'one' scopes it against multi-page siblings like sitemap_to_markdown, and the input schema confirms a single 'url' parameter.

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?

Gives a clear use context ('For LLM context and RAG'), which orients the agent toward content-extraction tasks. It stops short of naming alternatives such as html_to_rag, sitemap_to_markdown, or page_structured_extract, so there is no explicit when-not guidance.

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