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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior. The description adds meaningful caveats: it reports only relationships present in PubMed, and absence of a flag is not independent validation. This goes beyond the annotations by clarifying the tool's epistemic limits and output interpretation.

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?

Three sentences deliver the core function, a use case, and a crucial caveat. Every sentence contributes distinct value; no redundancy or padding. Information is front-loaded in the first sentence.

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?

The tool is simple (one param, no output schema). The description explains what integrity flags are checked, when to use it, and how to interpret results (reports only existing relationships; absence not proof). While it doesn't describe the exact output format, the behavioral caveat provides sufficient return semantics for an agent to select and expect results.

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 100% for the single parameter 'pmid', described as 'A single numeric PubMed ID.' The description does not add new parameter-level details beyond reinforcing that it operates on one PMID. Baseline of 3 applies given 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 tool's function: checking one PubMed citation for specific NLM-indexed integrity flags (retraction, expression of concern, erratum, update, duplicate publication, republished articles). The verb 'Check' plus enumerated link types uniquely scopes this tool relative to siblings like search_pubmed or get_abstract.

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?

Explicit usage guidance is given: 'Use before relying on a specific PMID in diligence or evidence synthesis.' This provides a clear context for when to invoke the tool. It does not explicitly name alternatives or when-not cases, but the instruction is actionable and distinct from sibling tools.

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