sacloud-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. It states this is a retrieval operation (取得), which implies read-only behavior, but doesn't explicitly confirm it's non-destructive. It doesn't mention authentication requirements, rate limits, error conditions, or what happens when parameters are invalid. The return format is mentioned ('VPNルータ一覧のJSONレスポンス'), but this is vague and potentially misleading since the tool retrieves monitor data, not a list of VPN routers.

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 well-structured and appropriately sized. It starts with a clear purpose statement, then has organized sections for Args and Returns. Each sentence earns its place by providing essential information. It could be slightly more concise by integrating the parameter explanations into a single paragraph, but the current structure is clear and efficient.

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 (4 parameters, no output schema, no annotations), the description is partially complete. It excels at explaining parameters but lacks important behavioral context. The return value description is potentially misleading ('VPNルータ一覧' suggests a list of routers, but the tool retrieves monitor data for a specific router). Without annotations or output schema, more detail about the response structure and error handling would be beneficial.

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 provides excellent parameter semantics beyond the schema. The schema has 0% description coverage (only titles), but the description explains each parameter: zone is the target zone, vpn_id is the resource ID, start is the start time in ISO format with default behavior, and end is the end time in ISO format with default behavior. This fully compensates for the schema's lack of descriptions. The only minor gap is not explaining what specific zone values are valid.

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: 'さくらのクラウドAPIからVPNルータ一のネットワーク流量のリソースモニタ情報を取得します' (retrieves VPN router network traffic resource monitor information from Sakura Cloud API). It specifies the verb (取得/retrieve), resource (VPN router), and type of data (network traffic monitor information). However, it doesn't explicitly differentiate from sibling tools like 'get_vpn_router_list' or 'get_router_monitor', which prevents a perfect score.

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. There are several sibling tools that might be related (get_vpn_router_list, get_router_monitor), but the description doesn't mention any of them or explain the specific use case for this tool. The only contextual information is the parameter descriptions, which don't constitute usage guidelines.

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