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

Annotations already cover read-only, open-world, idempotent, and non-destructive hints. The description adds behavioral context beyond annotations: it specifies the data source (api.plos.org) and that no auth is required, which is useful for an agent to know. It does not contradict annotations, and the added info is valuable, so a 4 is appropriate.

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?

The description is two sentences, front-loaded with the main action and resource, and includes key details (fields, source, auth) without any redundancy. Every sentence earns its place, and the structure is clean and scannable.

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?

Given the tool has an output schema (not shown but present), the description doesn't need to explain return values. It already mentions the fields included, the data source, and auth requirements. For a single-parameter detail lookup, this is complete and leaves no critical gaps for an agent to call it correctly.

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?

The input schema fully documents the 'doi' parameter with an example and description. The description adds extra value by clarifying that the DOI is the same as the one returned in plos-search.search results, which helps with chaining calls. This goes beyond what the schema provides, so a 4 is justified despite the high schema coverage.

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 clearly states the verb 'Get' and resource 'full detail for a single open-access PLOS article by DOI', listing specific fields (title, journal, publication date, authors, abstract, subject tags). This distinguishes it from the sibling plos-search.article.search, which presumably returns search results, by emphasizing 'single' and 'by DOI'.

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 description gives clear context for when to use this tool: when you have a DOI and want full article details. It does not explicitly mention alternatives or exclusions, but the context is clear enough for an agent to infer it should be used after a search or when a DOI is known. It lacks an explicit 'use search instead' note, so it's a 4 rather than 5.

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