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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds context about high-cardinality fields but doesn't disclose pagination behavior or response format beyond what the schema implies. With annotations covering the safety aspects, a 3 is appropriate.

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 sentences, front-loaded with the purpose, and every word earns its place. The first sentence states what it does, the second explains when to use it. No fluff.

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 has an output schema, so return values are documented. The description covers purpose and usage context. With 100% schema coverage and good annotations, the description is complete enough for an agent to select and invoke the tool correctly. The only minor gap is not listing example field values, but that's not necessary.

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%, so all four parameters are documented in the schema. The description adds the context that fields like NAICS are high-cardinality, which helps understand why the tool exists, but doesn't add parameter-specific meaning beyond the schema. Baseline 3 is correct.

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 returns allowed option values for B2B Persona Listgen filter fields, naming specific examples (NAICS, department, role). It distinguishes itself from the sibling b2c_listgen_options by specifying B2B, and the verb 'Return' is specific to the resource.

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 explicitly says 'Use this tool when you need the valid values for large, high-cardinality fields too big to embed directly in tool schemas,' which provides clear context for when to use it. It doesn't explicitly mention alternatives or when not to use it, but the context is sufficient given the sibling tools.

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