Semantic Corpus Search

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 by structured data. The description adds genuine value beyond annotations: it discloses the AI Search binding dependency, rate-limiting behavior, and crucially that a 503 means index unavailability rather than no match — an important interpretive insight for agents handling errors.

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 sentences, zero filler. The opening sentence states purpose and output, the second provides usage guidance, and the third covers dependencies and error interpretation. Every sentence earns its place with no redundant information.

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?

Despite being a single-param tool, it's sufficiently complex (retrieval strategy, ranking, dependencies, rate limits, error semantics) and the description covers all of these dimensions. With an output schema present, return-value explanation is unnecessary. The description is complete for an agent to select and invoke this tool correctly.

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% — the single query parameter is documented in the schema as 'A natural-language question or concept.' The description reinforces this with 'Vector + rerank' language and returning 'ranked source cards,' but doesn't add significant format or syntax semantics beyond what the schema already provides. Baseline 3 is appropriate given full schema coverage.

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 opens with a specific verb+resource+mechanism ('Vector + rerank retrieval over the whole corpus, returning ranked source cards'). It clearly distinguishes itself from sibling search_threats, which is described as 'boolean/exact over structured filters,' providing a strong sibling differentiation.

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?

Explicitly states when to use ('conceptual or paraphrased questions where the exact terms do not appear in the text'), when not to use ('when keyword search fails' implies use alternative first), and names the exact alternative (search_threats). This is textbook explicit when/when-not guidance.

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