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

Annotations already provide readOnlyHint and openWorldHint. The description adds behavioral context by specifying it returns only titles, PMIDs, and journals, and that it is a limited preview without a paid tier, which is beyond the annotations.

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 concise sentences that front-load the key information: it's a free preview of PubMed search and what it returns. No extraneous words.

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?

For a simple query tool with one parameter and no output schema, the description covers the main purpose and return items. It could mention ordering or limits, but overall it is adequate for a preview tool.

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 single parameter 'topic' is fully described in the schema as 'Biomedical topic or question'. The description adds no additional information about parameter format, constraints, or examples, so it stays at baseline.

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 it performs a real PubMed search and returns top article titles, PMIDs, and journals. It distinguishes itself as a FREE preview, differentiating from potential siblings like 'pubmed_evidence' which likely offer more extensive results.

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 implicitly indicates this is for quick previews by labeling it 'FREE preview' and noting 'No paid research tier is active'. However, it does not explicitly state when to avoid this tool or mention alternatives like 'pubmed_evidence'.

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