Research Paper & DOI Lookup (Crossref)

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

With no annotations provided, the description carries the full burden and does substantial work: it discloses the data source and scale (Crossref, 150M+ records), a concrete output-exclusion ('Abstracts are excluded'), and the commercial model ('Paid per call via x402 (USDC on Base)'). It leaves rate limits, error behavior, and paid-vs-unpaid request flow unmentioned, but the payment signature is covered by the schema.

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 source and capability, then the return fields, then usage triggers. The one-paragraph form is dense but every clause is informative; the long enumerated return list is the only mildly padded stretch.

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 must describe return values, and it does so thoroughly (title, authors with ORCID, journal/publisher, date, type, ISSN/ISBN, citation and reference counts, licence, full-text links, funders) while flagging the abstract exclusion. For an 8-parameter read tool with zero annotation coverage, nothing an agent needs in order to call it correctly is missing.

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 coverage is already 100%, so the baseline is 3; the description adds genuine semantics by framing doi as a resolution mode versus query/author/type/year as search filters, which the flat schema does not make explicit. It does not clarify that doi and the search filters are mutually exclusive, nor add syntax detail beyond the schema examples.

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 ('Scholarly works metadata from Crossref') and enumerates the two operating modes: resolve a DOI, or search by keywords/author/title with year and type filters. An agent knows exactly what the tool returns at a glance.

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 explicit triggering scenarios ('verify a citation or DOI, find papers on a topic, or get a paper's authors, journal, date, citation count and links'). It does not, however, state when NOT to use it or name an alternative for full-text/abstract retrieval, though the abstracts-excluded note partially covers that.

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