Sakila MCP Server

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 but provides minimal information. It states what the tool does but doesn't mention whether it's a read-only operation, what permissions might be required, whether there are rate limits, or what format the rental history data will be returned in. For a tool with 3 parameters and no annotations, this is insufficient behavioral context.

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 states exactly what the tool does without any wasted words. It's appropriately sized for a straightforward retrieval tool and gets directly to the point with no unnecessary elaboration.

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 read operation with good schema coverage but no annotations and no output schema, the description is minimally adequate. It tells the agent what the tool does but leaves important behavioral questions unanswered. The combination of clear purpose, complete parameter documentation in the schema, and concise description makes it functional but not comprehensive.

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 100% description coverage, with all parameters clearly documented in Japanese. The tool description doesn't add any additional parameter information beyond what's already in the schema. According to the scoring rules, when schema_description_coverage is high (>80%), the baseline is 3 even with no param info 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 verb ('取得します' - get/retrieve) and resource ('顧客のレンタル履歴' - customer rental history), making the purpose immediately understandable. It doesn't explicitly differentiate from sibling tools like 'get_customer_activity' or 'get_customer_details', but the specific focus on rental history is clear enough to avoid confusion.

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. With siblings like 'get_customer_activity' and 'get_customer_details' available, there's no indication of how this tool differs in scope or when it should be preferred over those other customer-related tools.

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