search_facets

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

Annotations already declare readOnlyHint=true, and the description adds a modest clarification that the tool returns counts rather than results. However, it does not disclose any additional behavioral traits such as aggregation logic or dependency on specific parameters.

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 a single, front-loaded sentence with no wasted words. It is appropriately concise, though slightly under-specified, so it does not receive a 5.

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?

Given the tool's 5-parameter complexity and zero schema descriptions, the description is far too brief. It does not explain return value structure (even though an output schema exists), nor does it provide usage alternatives or parameter behavior, leaving significant gaps for correct invocation.

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 input schema has 5 parameters with 0% description coverage, and the description provides no information about how any parameter affects the facet counts. The agent is left without guidance on what query_string, entity_names, category_id, etc., do.

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 states a specific verb ('return'), resource ('facet counts'), and purpose ('to help filter search results'), clearly distinguishing it from sibling tools like search_entities and search_suggestions.

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 phrase 'to help filter search results' implies a usage context, but there is no explicit guidance on when to use this tool instead of alternatives, and no exclusions are mentioned.

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