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

With no annotations, the description carries the behavioral burden. It does disclose the cost calculation source (Rakuten same-day cheapest unit prices) and unit (per serving, yen), which is useful. But it does not state how the result is presented, whether the content changes daily, or whether costs are estimates.

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 one compact sentence with the core purpose front-loaded and no filler. Every clause contributes: budget, daily menu, ingredient constraint, and cost derivation.

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 zero-parameter tool with no output schema, the description covers the essential expectations: a daily menu, a 500-yen budget, shelf-stable recipes, and a per-serving cost from Rakuten prices. It does not specify the exact response structure or the date dependency, but nothing critical is missing for making a first call.

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, so there are no parameter semantics to clarify and the schema fully covers this. The description still adds useful context about the cost unit, though it defines no arguments.

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 identifies a specific resource: a 500-yen daily menu, with recipes using shelf-stable ingredients and per-serving cost calculated from Rakuten prices. It is distinct enough from price/cost-focused siblings like cheapest and cost_item, though it lacks a clear tool verb such as 'returns' or 'generates'.

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 usage context is implied: this is for today's 500-yen menu and its ingredient cost. However, it gives no explicit guidance about when to choose it over alternatives, no prerequisites, and no exclusions.

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