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

Annotations already declare readOnlyHint=true and openWorldHint=false, so core safety behaviour is covered. The description adds useful context beyond that — no payment/charge is incurred and the exact returned payload is limited to a defined set of fields, i.e. a truncated view rather than the full article — but it discloses nothing about rate limits, auth, or failure modes.

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 telegraphic sentence with 'Free' front-loaded and no wasted words; each clause enumerates a distinct returned field. Slightly fragmentary style, but appropriately sized for a one-parameter read tool.

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 field enumeration is genuinely valuable and largely describes the return payload. However, it leaves the required articleId unexplained and says nothing about error behaviour (e.g. invalid or missing article), so it is adequate but not complete for a tool with one undocumented required parameter.

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% for the single required articleId, so the schema gives no meaning for the parameter. The description only alludes to it via 'for one article' without stating format, source, or how to obtain a valid ID, leaving the parameter essentially undocumented.

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 states exactly what is returned for one article: first two paragraphs, problem, audience, teaser and refund policy of a preview — a concrete resource with specific scope. It does not name the paid sibling (get_article) or explicitly contrast with it, so differentiation is implied by 'Free/No payment' rather than stated.

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?

'Free... No payment' implies this is the no-cost entry point versus a paid full-article tool, but the description never says when to choose this over get_article or search. Usage must be inferred from the pricing hint rather than an explicit when-to-use rule.

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