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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered structurally. The description still adds real behavioral facts beyond that: a hard cap of 20 results, the exact shape of each result (id, title, url), and the canonical URL pattern. It does not mention pagination or empty-result behavior, which keeps it from a 5.

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?

Purpose is front-loaded in the first clause, followed by constraints, result shape, canonical URL, and the follow-up call. Four sentences, each carrying distinct information, with no 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?

For a single-parameter search with an output schema present, the description covers everything the agent needs: what is searchable, the result cap, the result shape, the canonical identifier, and which tool to call next. Nothing material 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 description coverage is 100% and the single parameter is fully documented in the schema, including the 2-120 length bounds and the year-filters-period behavior. The description merely restates the character range, adding no syntax or formatting detail beyond what the schema already provides, so the baseline 3 applies.

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?

States a specific verb and resource ('Search published StatOrigin statistics') and enumerates the searchable facets (indicator, place, industry, source-sentence words). It also positions itself against the sibling fetch by explaining that search returns ids which fetch then resolves, so an agent can distinguish the two without inspecting 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?

Gives clear usage context and an explicit next step ('Call fetch with id to read the value...'), which is genuine routing guidance. It does not, however, say anything about when to prefer get_ranking over this tool, leaving one sibling unaddressed.

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