Search bioRxiv and medRxiv

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

Annotations already declare read-only, idempotent, open-world, non-destructive, so the safety profile is covered; the description earns credit for going further by disclosing the underlying Europe PMC index (which explains coverage of both servers and likely indexing gaps) and by stating what comes back — abstracts, DOIs, and whether a published journal version exists. It stops short of describing pagination mechanics or result-count limits beyond what the schema shows.

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?

Four sentences, front-loaded with the core capability, then syntax examples, then filtering/sorting/returns, then sibling routing. No sentence is redundant and the parenthetical about Europe PMC is placed where it explains rather than interrupts.

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 seven parameters, no output schema, and only 57% schema coverage, the description does the necessary work: it explains query syntax, filter scope, sort options, and the shape of results. The main residual gap is `page_size` and cursor-based paging mechanics, though `cursor` is documented in the schema 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 57%, so the description must carry some weight — and it does, most valuably by showing that `query` accepts Europe PMC syntax with two concrete example expressions (`TITLE:"single-cell" AND AUTH:"Regev A"`, `(organoid OR spheroid) AND ABSTRACT:"drug screening"`), which the schema only labels generically. It also clarifies that server filtering and dates apply to first-posted date and enumerates the sort modes. `page_size` is left undocumented, a minor gap.

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 opens with a specific verb and resource, 'Keyword search over bioRxiv and medRxiv preprints', and immediately qualifies the scope by noting it goes through the Europe PMC index. It then explicitly separates this tool's job from biorxiv_get_preprint (version history) and biorxiv_get_full_text (reading a paper), so an agent can route correctly without consulting schemas.

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?

It names two concrete alternatives and the conditions that select them: use get_preprint for version history and get_full_text to read a paper. The guidance is clear but incomplete as a routing map — it says nothing about when to prefer this search over biorxiv_list_recent or the arxiv_search sibling, which an agent comparing tools would want.

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