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

Annotations only cover readOnlyHint and openWorldHint; the description adds genuinely useful behavior beyond them: bodies are licensed Europe PMC text, and restricted/unavailable or arXiv papers return explicit metadata-only outcomes rather than failing. It does not mention rate limits or truncation of long passages.

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?

Two dense sentences with no filler: capability first, then invocation inputs, then fallback outcomes. Front-loaded and every clause earns its place.

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, return values needn't be documented, and the description still covers access scope, accepted input formats, and degraded outcomes. Only the limit parameter and question phrasing guidance are left uncovered.

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 0%, so the description must carry the load, and it does for two of three params — it enumerates accepted ID forms for paper_id (PMID, PMCID, DOI, canonical) and explains the question parameter drives question-ranked passage selection. The optional limit param is left unexplained.

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 (Read) and resource (a paper's licensed Europe PMC body text plus question-ranked passages), including the payload fields returned (source, license, byte locators). This is clearly distinguishable from siblings like research_search_papers and research_inspect_paper.

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 clear precondition for invocation: supply a PMID, PMCID, DOI or canonical ID plus a question. It also names when the tool degrades gracefully (restricted/unavailable bodies, arXiv papers). It does not, however, explicitly contrast with sibling tools such as research_inspect_paper or research_search_papers.

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