Nankai Trough Scale & Reach

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds that the tool provides sources and is an overview, but does not disclose additional behavioral traits such as response format, pagination, or any caveats. It does not contradict annotations, but adds limited behavioral context beyond them.

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 two sentences long, front-loaded with the primary result and a clear usage pointer. Every sentence earns its place: the first explains what the tool returns, the second explains when and how to proceed. No redundancy or filler.

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?

There is no output schema, so the description must convey the return value. It lists the key facts (probability, casualties, intensity-7 reach, tsunami) and mentions 'with sources', giving the agent a clear expectation. For a simple overview tool with one optional parameter and strong annotations, this is sufficiently complete.

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 schema provides 100% coverage for the single 'language' parameter with an enum and description. The tool description does not add any additional parameter semantics beyond what the schema already conveys, so the baseline score of 3 is appropriate.

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 uses a specific verb 'get' and identifies the resource as 'headline facts of the official 2025 Nankai Trough estimate', listing the content areas (probability, casualties, intensity-7 reach, tsunami) and sources. It clearly distinguishes itself from sibling tools by positioning as the starting point and even pointing to the next tool to call.

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: 'Start here to understand the scale' and then instructs to call official_hazard_maps for a specific address. This provides clear usage context, a sequential workflow, and an alternative tool for a different use case.

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