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

Annotations already declare readOnlyHint and openWorldHint, and the description goes beyond them with genuinely operational detail: pricing at $0.01 USDC per call via x402, no charge if the lookup services are down, and no AI in the loop. It does not cover latency, rate limits, or partial-failure behavior per id, so it is useful but not exhaustive.

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 the core action and tightly packed, though it is a long semicolon-chained sentence that mixes purpose, guidance, billing, and provenance claims. Every clause carries some information, but the density makes it slightly harder to scan than a split structure would be.

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?

There is no output schema, so the description carries the full burden and it does: it enumerates the returned fields (existence, title, authors, year, venue, citation count, retraction flag) plus cost and failure billing. An agent has everything needed to decide, call, and interpret the result.

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 both parameters are already documented in the schema, including the same-order requirement for titles and accepted id formats. The description restates the 1-10 bound and the title-comparison behavior rather than adding format or edge-case detail beyond the schema; baseline 3 applies.

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 ('Looks up 1-10 DOIs or arXiv ids') and enumerates exactly what is checked: existence, title, authors, year, venue, citation count, retraction status. It is clearly separable from siblings like check_links or check_quote without opening any 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?

Gives a concrete scenario ('Pass the titles you cited to see if they match the real ones. Catches made-up references'), which tells an agent when this tool is the right choice. It does not, however, name an alternative or state when to prefer a sibling such as check_quote for quoted text, so it stops short of full routing guidance.

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