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

With no annotations provided, the description carries the full burden of behavioral disclosure. It reveals that the data is limited to what is confirmed from official primary sources and that output includes a 2-digit prefecture code, which are useful constraints. However, it does not state whether the operation is read-only, the return format beyond the code, or any other behavioral traits.

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, compact sentence with no redundancy. It conveys the core resource, a source constraint, and an output detail efficiently. There is no waste, and the essential information is immediately accessible.

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 tool with no parameters and no output schema, the description provides some context: what it covers, source criteria, and an output hint. However, it lacks clarity on the exact structure of the returned data (e.g., a list of benefits per prefecture, fields beyond the code), which an agent would need to know to interpret results 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?

The tool has zero parameters, and schema coverage is trivially 100%. Baseline for zero parameters is 4, and the description does not need to explain parameters. The mention of '県コード2桁つき' pertains to output, not input, so it adds no parameter semantics but does not detract.

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 clearly identifies the resource as prefecture-specific benefits and support systems, and notes a source constraint (official primary sources) and an output hint (2-digit prefecture code). It distinguishes itself from siblings like gov_guide and gov_money by its specific focus on prefecture-level benefits, though it lacks an explicit verb like 'list' or 'retrieve'.

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 gives no guidance on when to use this tool over its siblings. It does not mention alternatives like gov_guide or gov_money, nor does it state conditions for selection. The context is implied but not explicit.

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