sacloud-mcp

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries full burden for behavioral disclosure. It clearly indicates this is a creation/mutation operation ('作成します'), but doesn't mention permission requirements, rate limits, error conditions, or whether the operation is idempotent. It does add useful context about prerequisite steps (checking plans/archives), which provides some behavioral insight beyond basic function.

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 with clear sections (purpose, usage instructions, Args, Returns). The Japanese purpose statement is concise, and the parameter documentation is organized. However, the bandwidth_mbps parameter appears in the description but not in the input schema, creating some confusion that slightly reduces efficiency.

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 7-parameter mutation tool with no annotations and no output schema, the description provides adequate but incomplete coverage. It explains the creation process and parameter semantics reasonably well, but lacks information about error handling, authentication requirements, and the structure of the return value (only stating it's a JSON response). Given the complexity, more behavioral context 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?

With 0% schema description coverage, the description must compensate for undocumented parameters. It provides specific guidance for 5 of 7 parameters: plan values (4 for standard, 2 for SSD), size_mb examples (20480 for 20GB), source_archive_id sourcing (from archive list), bandwidth_mbps options (100, 500, or 1000 Mbps), and name length constraints (1-64 chars). However, zone and server_id lack additional context beyond what's in the schema.

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でディスクを作成して、サーバーに接続します' (Create a disk using Sakura Cloud API and connect it to a server). It specifies both the action (create) and resource (disk), and distinguishes itself from siblings like create_server or create_router by focusing on disk creation with server attachment.

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 clear context on when to use this tool: it instructs to first retrieve disk plans and archive lists for user selection, and specifies that source_archive_id should come from an archive list. However, it doesn't explicitly state when NOT to use it or mention alternatives like get_disk for reading existing disks, which prevents a perfect score.

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