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

Annotations already declare read-only, idempotent, open-world, non-destructive behavior, and the description adds substantial context beyond that: the concrete data source URL (www.jma.go.jp/bosai/warning/data/warning/<office>.json), the exact status vocabulary (issued / continuing / lifted / no warnings in effect), the response granularity (sub-prefecture and municipality), and the full set of tracked categories. It also discloses the localization behavior (native Japanese names with English glosses), which materially helps an agent parse the response.

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 front-loaded — the first sentence states the core purpose — and every subsequent sentence adds operational value: return structure, data source, input formats, and localization. It runs about four dense sentences, and the category enumeration plus JMA gloss push it slightly past minimal length, but no sentence is wasted. Well-structured and informative.

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?

With only 1 parameter, no output schema, and rich annotations, the description carries the burden of defining the response contract — and it does so thoroughly: status vocabulary, category coverage, administrative granularity, accepted input formats, and source provenance are all specified. An agent can call this tool and interpret its output without opening any schema or making assumptions.

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?

Schema description coverage is 100% — the schema already documents 'area' as a place name or JMA area/office code with examples. The description largely corroborates this rather than adding new meaning, contributing only the note that resolution works 'the same way as jma_resolve_area,' which connects the parameter semantics to a sibling tool. This matches the baseline-3 case where the schema carries the heavy lifting.

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 states a specific verb-resource pair ('Current weather warnings and advisories for a Japanese region') and enumerates exactly what is returned: headline bulletin plus per-area status for every JMA category at two administrative levels. It clearly distinguishes itself from siblings like jma_forecast (forecasts) and jma_earthquakes (earthquakes) by domain, while its explicit reference to jma_resolve_area shows how it relates to that sibling. No ambiguity about what this tool does.

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 gives clear context for use: it is for current warnings/advisories, not forecasts or earthquake data, and it explicitly names jma_resolve_area as the tool whose resolution behavior it shares. However, it never states explicit when-not-to-use rules or directly points to jma_forecast/jma_earthquakes as alternatives for other weather data needs, leaving that to inference from the tool names and domain wording.

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