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

Annotations already cover read-only and open-world, but the description adds substantial behavior beyond them: a per-call price ($0.002 USDC via x402), the billing rule that failed calls are free, the partial-enrichment cap (only the first 5 matches get summary/author/last-reviewed/paywall), and the login-driven content limitation. These are exactly the facts an agent needs before spending money or expecting richer payloads.

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 purpose, then the details toggle, the scope ceiling, and finally pricing — a sensible order with no filler. The pricing sentence is long but every clause (currency, networks, failure policy) carries decision-relevant information.

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 an output schema present, the description need not explain return values, and it doesn't. It still covers the pieces the schema cannot: indexing source, the metadata-only ceiling, partial enrichment on details, and the payment model — everything needed to call this correctly and knowingly.

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 the parameters are already fully documented, giving a baseline of 3. The description merely restates the title-word filter and the 'first 5' behavior of details without adding format, syntax, or matching semantics beyond 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 and resource ('Medscape eMedicine clinical articles by specialty') plus the exact fields returned (title, topic category, article id, URL) and the filter mechanism (words in the title). Against a fleet of sibling search_*_articles tools, this distinguishes itself by source, domain (clinical specialty index) and by explicitly capping scope to metadata.

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?

Clear usage context: specialty is the entry point and q narrows by title words, and the 'Metadata only, no article text (Medscape articles need a free login)' clause tells the agent when this is not the right tool for full text. It does not, however, name an alternative sibling (e.g. search_pubmed_article_metadata) or state when to prefer another source, so it stops short of explicit routing.

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