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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered; the description still adds real value by disclosing region-level granularity, that the max level is derived and not country-wide, infectious-disease notices, tracking_since self-history, freshness and sources.

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?

Purpose is front-loaded, though the opening is phrased as a question rather than an imperative. The return-value inventory is dense but each clause is informative and the disclaimer closes the scope cleanly.

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 an output schema present and rich annotations, the definition is more than complete for calling the tool; return contents are enumerated (somewhat redundantly with the output schema) and the disclaimer prevents misuse as travel advice. Only the sibling relationship is left implicit.

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% and the single country parameter is fully documented (alpha-2, alpha-3, US-HI, 4-digit MOFA code, US mainland/Hawaii behavior). The description's restatement of the code formats adds no meaning beyond the schema, so the baseline 3 applies.

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?

States a specific verb (look up / which level) and resource (Japan MOFA region-by-region danger levels) with the accepted identifier formats. It does not name or contrast with the sibling mofa_level_changes, so the agent must infer the split, keeping it below a 5.

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?

Usage is implied by the lookup framing and the limitation 'relays MOFA; no danger assessment or travel advice', but there is no explicit when-to-use-this-vs-mofa_level_changes guidance and no stated prerequisites or exclusions beyond the disclaimer.

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