Fetch AI-parsed page data

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

Annotations already cover the safety profile (readOnly, non-destructive, openWorld), and the description adds genuinely non-obvious behavior: the graceful degradation to rendered HTML when no structured data exists, plus a billing implication tied to fetch_html. It does not discuss rate limits, proxy/auth requirements, or latency, so it is strong but not exhaustive.

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?

Three tight sentences: capability and output format first, target use case second, fallback/billing caveat last. Every clause carries information an agent needs, with no restatement of the title or 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?

With no output schema, the description correctly carries the return-value burden by describing structured JSON, its fallback, and cost behavior. The one remaining gap is that the shape of the parsed JSON (field naming, nesting) is left unspecified, though that is arguably discoverable from the response itself.

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, rules_hint, and proxy_country are already fully documented in the schema. The description implies rules_hint's guiding role but adds no syntax, format, or edge-case detail beyond the structured fields, so the baseline of 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?

Specific verb (fetch) plus explicit output contract: AI-parsed structured JSON rather than raw HTML, with examples (product details, article content). It implicitly distinguishes itself from fetch_html by naming that alternative's output format, so an agent can tell the two apart without opening a schema.

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?

"Best for extracting fields from product, listing or article pages without writing your own HTML parsing" gives clear positive selection criteria, and the fallback sentence tells the agent what happens on pages lacking structured data. It stops short of an explicit "use fetch_html when you want raw HTML" routing statement, which keeps it from a 5.

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