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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, yet the description adds genuinely new behavior: it runs a named Apify Actor on the caller's own account at pay-per-event $0.001/article and that failed URLs are not billed. It stops short of describing partial-failure behavior, latency, or whether per-URL results include error entries.

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 dense sentences: what comes back, the failure/billing caveat, then the execution and cost model. Return fields are front-loaded and every clause carries information an agent can act on.

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 enumerating the returned fields, and it discloses the cost and actor-execution model. It leaves gaps around error/partial-success semantics and the 25-URL batch ceiling, which matter for a multi-URL extraction call.

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 all three parameters are already documented and the baseline of 3 applies. The description adds no guidance on maxChars truncation effects or when the apify_token fallback is needed, so it does not exceed the 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 (extract) plus the exact resource and enumerates the returned fields: title, author, published date, body text, word count, content hash. That makes the output shape unambiguous, but it never contrasts itself with the closest sibling extract_website_content, so an agent must infer the article-vs-page distinction.

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?

Usage is only implied by the parameter name articleUrls and the 'article' framing; there is no explicit statement of when to pick this over extract_website_content or extract_web_metadata, nor any note about non-article pages failing. The billing note is cost guidance rather than selection guidance.

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