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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only states the content returned (list and median) and does not mention whether the operation is read-only, how 'that day' is determined, what units or format are used, 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 short sentence with no filler or repetition. It front-loads the core output content and is appropriately sized for a zero-parameter tool.

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?

The description is minimally viable: an agent learns the tool returns a list of daily necessity terms and a median value. However, with no output schema and no annotations, it omits what the median refers to, the expected output shape, and how this tool relates to similar siblings.

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 input schema has zero parameters, so there is nothing for the description to explain about parameter semantics. The baseline of 4 applies because no parameter documentation is needed; the description's reference to 'that day' is not a parameter but an implicit context.

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: a list of daily necessity terms and the day's median value. It conveys the tool is a data-retrieval/index lookup, though it lacks an explicit verb. It does not differentiate itself from the sibling tool 'nichiyo'.

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 guidance on when to use this tool versus siblings such as 'nichiyo', 'prices_now', or 'cost_item'. No conditions, exclusions, or alternative recommendations are provided, leaving the selection decision largely to inference.

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