rakuten-mcp

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. While it indicates this is a search operation (implying read-only), it doesn't mention any rate limits, authentication requirements, pagination behavior beyond the 'page' parameter, or what the response format looks like. For a search tool with 6 parameters and no output schema, this leaves significant gaps.

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, efficient sentence that conveys the essential purpose without any wasted words. It's appropriately sized for a search tool and gets straight to the point.

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 that this is a search tool with 6 parameters, no annotations, and no output schema, the description is insufficiently complete. It doesn't explain what information is returned, how results are structured, or provide any behavioral context beyond the basic purpose. The agent would need to guess about the response format and operational characteristics.

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 schema description coverage is 100%, so all parameters are well-documented in the schema itself. The description adds no additional parameter information beyond what's already in the schema descriptions. According to the scoring rules, when schema coverage is high (>80%), the baseline score is 3 even with no parameter information in the description.

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 the action ('Search for products') and the target resource ('on Rakuten Ichiba'), with helpful context about it being Japan's largest e-commerce marketplace. However, it doesn't explicitly differentiate from sibling tools like 'search_books' or 'search_travel', which are also search tools on the same platform.

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 provides no guidance on when to use this tool versus alternatives like 'search_books' or 'search_travel'. It doesn't mention any prerequisites, exclusions, or specific use cases that would help an agent choose between these similar search tools.

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