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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the read-only, external-network profile is known. The description usefully adds that no API key is required, that only metadata (not full text) is returned, and a precise billing rule ($0.002 USDC per successful call, failed calls free) — real value beyond annotations. However, it says nothing about rate limits, result ordering, or pagination behavior, which matter for an open-world search.

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 and returned fields before the alternative tool and pricing details, which is the right order. The single dense opening clause is efficient, though the pricing sentence and sibling comparison make the block longer than the core task requires.

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 and full schema parameter coverage, the description does not need to explain return shapes, and it appropriately focuses on scope, source coverage, cost, and the nearest alternative. The remaining gap is guidance on query construction and result limits for an open-world search over a large DOI corpus.

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%: both `q` (1–200 characters) and `limit` (1–25, default 5) are documented in the schema. The description adds no query-syntax or matching-behavior guidance (e.g., boolean operators, fielded search), so the baseline 3 for high-coverage schemas 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 (DataCite DOI search) and enumerates the returned fields — DOI, title, publication year, resource type, publisher, creators, landing page — plus the covered content domains (datasets, software, other research outputs). The 'Metadata only' qualifier and the named sibling make it easy to tell apart from the surrounding scholarly/news search tools.

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?

Explicitly routes one alternative case: use search_pubmed_article_metadata when you need PubMed article metadata by PMID. That is clear conditional guidance, but only one of many closely related siblings (search_crossref, search_figshare_articles, search_unpaywall) is addressed, and there is no statement of when-not-to-use or of query syntax expectations.

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