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

Annotations already declare readOnlyHint, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds meaningful behavioral context beyond that: it is a closed site-internal search whose results are grounded in page text and URLs, and it explicitly warns against supplementing with information not present on the site.

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 sentence, followed by scope enumeration and answer-grounding instructions. The long topic list is somewhat dense but each item usefully delimits searchable scope, so little is pure 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?

With an output schema present, return values need no explanation, and annotations cover the safety profile. The description supplies scope, grounding expectations, and anti-hallucination guidance, leaving only the sibling-disambiguation gap ('search_pages') as an incompleteness for this low-complexity, single-parameter tool.

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 the single 'query' parameter already carries its own example (料金 支払い方法), so the schema does the heavy lifting. The description lists topics to search but adds no syntax, format, or matching semantics beyond what the schema provides, which is the baseline 3.

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 (検索する) and resource (Pono-Pono公式サイト内) and even enumerates the content domains in scope, so the agent knows exactly what is searched. However, it never differentiates itself from the near-identical sibling 'search_pages', leaving ambiguity about which search tool to pick.

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 rich context on what to look for and how to select results (prioritize pages matching the question, verify grounding text and URL, separate product info from general explanation, avoid speculation). But this is guidance for interpreting results, not for choosing this tool over 'search_pages', 'fetch', or 'get_page', so usage routing remains implied.

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