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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds pricing/cost context ('Free on all plans') which is genuinely useful behavioral info, but does not describe pagination, result ordering, or what happens when text is omitted.

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 clauses: purpose, benefit, cost/endpoint. Front-loaded with the value proposition and zero 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?

Complete enough for a simple read-only lookup: purpose, cost, and endpoint are stated, and the return concept (values + counts) is described despite no output schema. Minor gap is absence of pagination/ordering behavior, but nothing critical is missing.

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%, including a documented field list and a partial-text example. The description adds no parameter-level detail beyond the schema, so baseline 3 is appropriate.

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+resource ('Get suggested values for a search field') with the added distinction of returning record counts. Clearly separates itself from the sibling search/enrich tools, which return records rather than suggestion values.

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?

Explicitly frames the use case: 'useful for building valid Person/Company Search queries.' This tells the agent when to reach for it (pre-query, to construct valid values), though it doesn't explicitly name or exclude alternatives.

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