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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds genuinely useful non-schema context: a free-sample quota and a per-call price ($0.002 USDC via x402), which matters for agent call budgeting. It stops short of describing result format or pagination.

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 tight sentences, front-loaded with what is returned before the cost caveat. No filler.

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, the description needn't explain return values, and it covers input syntax and cost. It is adequate for a 1-parameter tool, with only sibling differentiation and result-count/limit behavior left unaddressed.

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% and the single 'term' parameter is described only as 'Query'. The description adds real value by noting support for PubMed query syntax, which tells the agent the accepted input format beyond the schema's minimal label.

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?

Clearly states it returns PubMed ids matching a query, which is a specific verb+resource+return type. However, it does not differentiate itself from close siblings like pubmed__pmc-search, pubmed__clinical-trials-search, or pubmed__summary, so an agent must infer the distinction from names alone.

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?

There is no guidance on when to use this versus the many sibling search tools (PMC, clinical trials, summary). Usage is only implied by the mention of PubMed query syntax; no prerequisites or exclusions are stated.

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