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

Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds critical behavioral context beyond annotations: the x402 micropayment requirement (0.015 USDC on Base) and the use of fast LLM parsing for schema mapping. It omits rate limits and failure modes, but those are not essential given the annotations and output schema.

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 front-loaded with the core action and the key payment constraint, then organized with use-case and parameter sections. It is efficient, though the opening sentence and the second sentence ('Extracts clean content...') are slightly redundant, and the parameter descriptions mostly duplicate the input schema.

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 the full input schema, annotations, and output schema, the description covers the essential operational constraints: purpose, payment, and when not to use it. It would be more complete with explicit notes about limitations on 'any webpage' (e.g., dynamic rendering, auth walls) and clearer differentiation from sibling scraping tools.

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 structured schema already documents all parameters. The description's parameter list mostly restates the schema — url, schema, and optional instructions — without adding meaningful new semantics such as examples, formats, or edge-case behavior.

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 opens with a specific verb and resource: 'Extract structured JSON data matching a custom schema directly from any webpage.' This distinguishes it from siblings like read_web_page or search_web because it emphasizes schema-driven structured extraction, not just fetching or searching.

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 provides explicit 'When to use' and 'When NOT to use' guidance, including the exclusion of open-ended chat without a defined schema. However, it does not name alternative sibling tools or explain when to prefer read_web_page or fetch_stealth_web, so it stops short of full alternative routing.

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