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

Goes well beyond the readOnlyHint/openWorldHint annotations by disclosing cost mechanics (x402, $0.005 per successful call, first 5/day free), determinism ('no LLM'), and the truncation flags (headingsTruncated, linksTruncated, truncated). Pricing and side-effect profile are exactly the context an agent needs before invoking.

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?

Front-loaded with the core action and output shape, and every sentence carries information. The final return-shape enumeration is long but justified because no output schema exists.

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?

With no output schema, the description correctly compensates by spelling out the full JSON return shape and truncation behavior. It stops short of describing failure behavior for non-public or blocked URLs, which is the only remaining gap.

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 url, includeLinks, and maxCharacters are already fully documented with defaults and bounds. The description adds no parameter-level meaning beyond the schema, so the baseline 3 applies.

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 a public web page and return structured data') and enumerates exactly what is returned: metadata, Markdown, headings, links. It does not, however, name or differentiate itself from its siblings extract_url and inspect_url, so an agent cannot tell from the description alone which sibling to pick.

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?

No explicit when-to-use or when-not-to-use guidance appears, and the two sibling tools (extract_url, inspect_url) are never referenced. An agent is left to infer that 'structured' output is the distinguishing feature.

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