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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds a non-obvious behavioral constraint not present in the schema ('requires at least one meaningful search parameter'), which is genuinely useful since required=0 would otherwise suggest an unrestricted call is valid. It does not describe return shape or pagination behavior, so not a 5.

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 tight sentences with the capability statement front-loaded, then routing, then the hard constraint. Very efficient, though the trailing 'NPPES Read API v2.1' is version trivia that contributes little to invocation.

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 read-only, 14-parameter search with full schema coverage, the description covers capability, routing, and the minimum-parameter constraint. The one gap is that no output schema exists and the description never says what a result looks like (provider record shape, count behavior), which an agent composing downstream steps would benefit from.

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 description coverage is 100% with enums and patterns on the tricky fields, so the schema carries parameter meaning almost entirely. The description only summarizes criteria categories (name, NPI, taxonomy, location) at a level the schema already conveys, adding no syntax or format detail. Baseline 3 applies.

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?

Specific verb ('search') + resource (NPPES NPI Registry) + explicit scope ('ANY combination of criteria' with the criteria domains enumerated). It directly names the two sibling tools it is not and the condition that selects it, so an agent can distinguish it without opening a schema.

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 routing: 'Use nppes_search_individuals / nppes_search_organizations for the common cases; use this when you need mixed or advanced criteria.' This is a textbook when-to-use/when-not statement naming the alternatives.

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