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

Annotations already establish the safe read-only/idempotent profile, so the bar is lower. The description usefully adds behavioral detail: a hard maximum of 20 results and the fact that for writing/mixed formats each word is returned with its grade-appropriate blankable character, which annotates the output shape meaningfully.

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 single sentence is front-loaded with the core action and packs result count plus return behavior without filler. It is dense but every clause carries information, though the run-on structure is slightly harder to parse.

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 no output schema, the description carries the burden and does explain the return content (up to 20 words with blankable characters per format). It stops short of clarifying edge cases like zero matches, but overall it is sufficient for calling the 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 description coverage is 100%, so the schema already documents grade, query, and the format enum. The description restates the same concept (grade + test format + character/word) without adding syntax or constraints beyond the schema, 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?

The description gives a specific verb (探す/find) and resource (words usable as problems for a given grade and test format), plus a concrete cap of 20 results. It is clear what the tool returns, but it never distinguishes itself from siblings like create_kanji_worksheet_from_words or find_math_problem_types.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no alternatives are named. The only implicit signal is that it takes a grade and test format, leaving the agent to infer this is a pre-worksheet search step from such context alone.

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