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

Annotations already cover the safety profile (readOnlyHint, idempotentHint), and the description adds value beyond them by listing exactly what is returned, which matters since there is no output schema. The at-least-one-input constraint is also disclosed behavior rather than restated schema. It stops short of describing pagination limits or result ordering.

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 short sentences, each with a distinct job: what it searches, what it returns, what must be supplied. The constraint is placed last where it reads as a call condition and nothing is padded.

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 search tool with five optional parameters, the definition covers purpose, return shape, and the one hard input rule. The remaining gap is pagination behavior and default page_size, which the schema handles adequately, so 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 coverage is 100%, so the baseline is 3, and the description exceeds that by stating a cross-parameter rule the schema cannot express: at least one of query or category_name must be supplied even though neither is required at the schema level. It adds no format detail for query beyond what the schema already says, keeping this at 4 rather than 5.

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 names a specific verb and resource ('Search vape brands on Vaper.club') and enumerates the matchable fields (name, alias, company name). The resource-based naming cleanly separates it from search_posts, search_products and search_shops, though it never explicitly states that separation.

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?

It gives one real precondition — 'At least one of query or category_name is required' — which is genuinely useful usage guidance. Beyond that it offers no when-to-use context and no pointer to get_brand_details for the detail view, so the agent must infer the boundary with siblings.

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