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 does state that the tool 'returns an overview' and describes the service, which implies a read-only informational call, but it does not explicitly disclose side-effect-free behavior, authentication needs, or output format.

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 first sentence front-loads the core purpose and the final sentence gives usage guidance. The middle sentence is a somewhat promotional explanation of Zippa's features, adding context but longer than strictly necessary.

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 no-parameter overview tool, the description covers what it returns and when to use it. It does not detail the exact contents of the returned overview, but the service summary in the description largely compensates.

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 tool has zero parameters and schema description coverage is 100%, so there is nothing for the description to add. The baseline of 4 applies for a parameterless tool.

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 opens with '「Zippa（ジッパ）」の概要を返します', naming a specific verb (returns overview) and resource (Zippa). It clearly distinguishes itself from page-level siblings like get_page, list_pages, and search_pages by framing this as a service-level overview rather than a page operation.

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 explicitly states when to use it: 'どんなサービスかを最初に知りたいときに使います' (use when you first want to know what the service is). This is clear context, though it does not explicitly name alternatives or exclusions.

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