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. The description adds value by clarifying the search scope (Japan foliage spots) and the return behavior (matching ids, titles, URLs), but it does not disclose pagination, result limits, or how partial matches are ranked. With annotations covering the key behavioral traits, a 3 is appropriate – the description adds some context but not deep behavioral detail.

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 a single dense paragraph that front-loads the core purpose before giving examples. It is concise, with no filler or repetition of schema fields. However, the example list and the return-value detail could be slightly tightened without loss, which prevents a 5.

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, read-only search tool with no output schema, the description is quite complete: it covers input semantics, return values, and the next-step workflow (fetch with an id). It does not specify result count limits or ordering, but given the tool's simplicity and annotation coverage, these are minor gaps. An agent can invoke this tool correctly with confidence.

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% for the single parameter (query described as 'Free-text search query'), so the schema already documents the parameter. The description adds meaning by detailing what kinds of free text are valid (names, prefectures, regions, months) and providing examples, which supports but does not fully compensate for the schema's minimal description. Baseline 3 is appropriate since the description enriches but does not dramatically extend 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 states a specific verb ('Search'), a clear resource ('Japan autumn-foliage viewing spots'), and the exact input type (free text matching spot names, prefectures, regions, or months). It also distinguishes itself from siblings by specifying what it returns (spot ids, titles, page URLs) and how to proceed to full details via fetch, so an agent can tell it apart from sibling tools like get_coverage or fetch.

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 explicitly says when to use this tool ('by free text') and what kinds of queries are appropriate ('a spot name, a prefecture, a region, or a month such as November'). It also gives example queries and states the follow-up action ('pass an id to fetch for the full forecast'), implying when a sibling tool like fetch is needed instead. This provides clear context without being wordy.

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