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

No annotations are provided, so the description carries the burden. It discloses data sources (気象庁), update frequency (10分ごと), time window (直近7日), and geographic scope (県ごと). It does not disclose output format, whether it returns both warnings and earthquakes together, or any rate limits. The disclosed traits are useful but not comprehensive.

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 a single compact sentence that packs in source, update frequency, time window, and geographic granularity. It is front-loaded with the main subject. Slightly dense due to the colon and parentheticals, but every element adds information. No wasted words.

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 zero-parameter, no-output-schema tool, the description covers the main query intent: current warnings and recent earthquakes. It doesn't specify the exact output structure (e.g., list vs. object, units, coordinate format), but with no schema or output schema, an agent can still call it correctly since there are no inputs. The main gap is not stating whether both data types are always returned together or how to interpret the results.

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 0 parameters, so the schema provides no parameter semantics. The description compensates by explaining what data is returned and its scope. With no parameters to document, a baseline of 4 is appropriate because the description fully clarifies what the tool does without needing parameter details.

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 provides current Japan weather warnings/advisories (by prefecture, every 10 minutes) and recent 7-day earthquake data (intensity, epicenter, coordinates). The verb is implicit but the resource and scope are specific. It doesn't explicitly differentiate from siblings, but the domain (Japan weather/earthquakes) is distinct enough among the listed siblings.

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 implies usage: when you need current Japan warnings or recent earthquake info. It doesn't explicitly state when not to use it or name alternatives, but the context is clear enough for an agent to select it for weather/seismic queries. No exclusions or alternative routing are provided.

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