List recent bioRxiv/medRxiv preprints

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

Annotations already declare read-only, idempotent, non-destructive, open-world behavior, so the safety profile is covered. The description adds genuinely useful context beyond that: default window of today, fixed page size of 30 records, and the cursor-continuation pattern, including the implied `next_cursor` value returned in results despite there being no output schema. It stops short of noting any result ordering or whether an empty window returns an empty page, which keeps it from a 5.

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 compact sentences: purpose and filter first, then defaults, then pagination, then sibling routing. Every sentence carries information an agent needs, and nothing is repeated from annotations or the 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?

For a zero-required-parameter listing tool with no output schema, the description covers the things an agent would otherwise have to guess: the time window default, page size, how to continue paging, and when to prefer search. Annotations plus schema plus this text leave no material gap for correct invocation.

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 67%, so some compensation is required, and the description supplies it: concrete category values for both servers, the 'defaults to today' behavior for the date window, and the mechanics of passing the cursor back in. It does not explain the `days`-versus-`date_from` alternative or the `server` switch, but both are documented in the schema itself.

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?

Brevity is not the issue here: the description states a specific verb ('List preprints'), the two resources (bioRxiv/medRxiv), the scoping dimension (a date window) and the optional category filter. It also explicitly distinguishes itself from biorxiv_search, so an agent can choose between browsing and querying without inspecting either 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?

The final sentence gives an explicit when-to-use ('browsing what is new') and a named alternative with its selecting condition ('use biorxiv_search for keyword queries'). The default (today) and the alternative date parameters are also flagged, leaving little to inference for the primary routing decision.

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