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

Annotations already declare the tool read-only, idempotent, and non-destructive. The description adds behavioral context by specifying that facets are query-dependent and that category paths come in ltree format for integration with cf_search_offers. It does not contradict annotations and covers key behavior beyond the safety profile.

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 exactly two sentences, front-loaded with the tool's action and followed by a clear usage rationale. Every word contributes value, with no redundancy or 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?

The tool is simple, has an output schema, and strong annotations. The description covers the essential purpose, integration nuance (ltree), and usage context. It lacks explicit behavior for edge cases like empty queries, but that is likely handled by schema and output schema, so overall completeness is high.

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% with descriptive parameter descriptions, so the baseline is 3. The description only adds a subtle nuance by calling brands/categories 'current filters,' implying they constrain facets, but this is marginal. No significant extra meaning is provided beyond the schema.

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 retrieves search facets (brands, categories, price range) for a query. It explicitly differentiates from siblings by noting the ltree 'path' for cf_search_offers.categories, making its role and output specific.

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 provides an explicit usage trigger: 'Use this when a shopping request is broad or ambiguous and you need the exact category path before searching.' This not only tells when to use the tool but also implies when to defer to cf_search_offers, giving clear alternative guidance.

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