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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds nothing beyond the parameter modes — no word on what happens with JS-rendered pages, rate limits, or whether a preset/schema omission causes failure, which matters for an open-world web tool.

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 compact sentence with the resource and the two mode options front-loaded, no filler. It errs toward under-specification rather than verbosity, so the structure is efficient but thin.

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 0%-documented 4-parameter open-world extraction tool, the description should at minimum explain available presets, the expected schema format, and timeout semantics. The output schema relieves it of explaining return values, but the input side is left largely unexplained.

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 0%, so the description carries the full burden, yet it only gestures at 'preset (article, product, ...)' and 'a field schema'. The required 'url' and the 'timeout_seconds' parameter are never mentioned, and the accepted preset vocabulary and JSON-schema shape remain undefined.

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+resource ('Extract structured fields from a URL') and clarifies the two extraction modes (preset vs. field schema). It never names the adjacent siblings fetch_url or scrape_url, so differentiation is left to inference from 'structured fields'.

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 phrase 'structured fields' implies when this belongs (schema-shaped extraction rather than raw page fetching), but there is no explicit when/when-not and no mention of fetch_url or scrape_url as alternatives. An agent must guess whether this is a superset or a sibling of those tools.

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