Sakila MCP Server

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 states the tool searches customers with filtering, but lacks details on permissions, rate limits, pagination, or response format. For a search tool with 5 parameters and no output schema, this leaves significant gaps in understanding how the tool behaves operationally.

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 concise and front-loaded, stating the core purpose in the first phrase. It uses only two sentences with no wasted words, making it efficient. A score of 5 is reserved for exceptional cases with perfect structure, but this is very good.

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 tool's complexity (5 parameters, no annotations, no output schema), the description is insufficient. It doesn't explain return values, error handling, or behavioral constraints. For a search tool that likely returns lists of customers, more context is needed to guide effective use, especially with sibling tools that might overlap in functionality.

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 description mentions filtering by name, email, and store, which aligns with three of the five parameters. However, schema description coverage is 100%, meaning the schema already documents all parameters thoroughly. The description adds minimal value beyond the schema, so it meets the baseline score of 3 for high schema coverage.

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 tool's purpose as 'search customers' (顧客を検索します) and mentions filtering capabilities by name, email, and store. It's specific about the verb (search) and resource (customers), but doesn't explicitly distinguish it from sibling tools like get_customer_details or get_customer_activity, which is why it doesn't reach a score of 5.

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. It mentions filtering capabilities but doesn't specify scenarios, prerequisites, or exclusions. For example, it doesn't clarify if this is for broad searches versus specific lookups, or how it differs from get_customer_details for individual customer queries.

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