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. It states the tool retrieves a list and identifies films not rented for a long time, but doesn't disclose behavioral traits such as whether it's read-only, if it requires specific permissions, rate limits, or what the output format looks like. For a tool with no annotation coverage, this leaves significant gaps in understanding its operation.

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, consisting of two sentences that directly state the purpose and key functionality. There is no wasted language, and it efficiently communicates the core intent without unnecessary details.

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 moderate complexity (2 parameters, no output schema, no annotations), the description is minimally adequate. It covers the purpose but lacks details on usage guidelines, behavioral transparency, and output expectations. With no output schema, the description should ideally hint at return values, but it doesn't, leaving room for improvement.

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 clear documentation for both parameters (days_not_rented and store_id). The description adds no additional parameter semantics beyond what's in the schema, such as explaining the impact of the days_not_rented threshold or store_id selection. Baseline 3 is appropriate as the schema does the heavy lifting.

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: '低稼働作品一覧を取得します' (get a list of underperforming films) and specifies the criteria: '長期間レンタルされていない作品を特定できます' (identify films not rented for a long period). This is a specific verb+resource combination, though it doesn't explicitly differentiate from siblings like 'get_popular_films' or 'get_inventory_turnover' beyond the underperforming focus.

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 doesn't mention sibling tools like 'get_popular_films' for contrast, prerequisites for use, or scenarios where it's most applicable. The user must infer usage from the purpose alone.

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