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

With no annotations, the description takes the full burden. It clearly indicates the tool is read-only (returns a list) and specifies the output fields. It does not mention pagination or potential errors, but for a zero-parameter list tool, this is adequate.

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 three sentences, front-loaded with the core purpose, then details and usage suggestion. Every sentence adds value with no redundancy.

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?

Given the simplicity (no parameters, no output schema), the description covers the essential: what it does, what it returns, and when to call it. It could mention edge cases like empty lists, but is otherwise complete for effective use.

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 no parameters, and the input schema has 100% coverage. The description does not need to add parameter details. The baseline for zero parameters is 4.

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 states it returns a list of public shops on the JPYC EC Platform, specifies the types of shops (direct-from-producer, specific product categories), and lists the included fields. It differentiates from siblings like get_shop and list_products_in_shop by positioning itself as the entry point for product searching.

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 explicitly advises calling this tool first as a starting point for product search, implying it should be used before more specific tools like get_shop or list_products_in_shop. However, it does not explicitly mention when to avoid using it or provide alternatives for other scenarios.

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