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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the description's added value is in disclosing the return shape (id, title, type, score, snippet) and the meaning of an empty hit list. That is real context beyond the annotations. It stops short of covering result-size behavior at the limit boundary or the fact that ranking can degrade to keyword-only, though the latter is documented in the schema.

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?

Four sentences, front-loaded with the purpose, then usage, then return contract, then the empty-result edge case. No sentence is filler and nothing important is buried.

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?

Six parameters with full schema coverage and no output schema, so the description must carry return semantics, which it does by naming the five hit fields and explaining the empty list. Combined with explicit sibling routing, an agent has everything needed to call it correctly and interpret the response.

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% and each of the six parameters, including the mode enum and its semantic-to-keyword fallback, is documented in the schema. The description adds only the notion of 'free-text query' and says nothing about mode, tags, type, product, or limit, so this is the baseline case where the schema does the work.

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?

Specific verb ('Search') plus specific resource ('the product knowledge vault') qualified by 'free-text query'. It also names what comes back (ranked hits) and explicitly separates itself from get_concept and get_context, so the agent can choose without opening other schemas.

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 condition is stated directly: use this 'when you need product knowledge but don't yet know which concept ids exist.' It then routes to the two natural alternatives, get_concept for one full note and get_context for an assembled briefing, which is an explicit when/when-not split.

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