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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered. The description adds real behavioral context beyond that: it names the two data sources (UK FCDO alert + review date, US State Department level + update date), mentions official links, and clarifies the audience caveat that UK advice targets British citizens and US advice targets US citizens.

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?

Front-loaded with purpose, then usage, then inputs, then return contents, then the sibling alternative and audience caveat. Every sentence carries information; the example phrases slightly pad it but illustrate intended queries legitimately.

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 annotations carrying the safety profile, the description need not enumerate return fields in detail. It still summarizes both advisory sources, the citizen-audience caveat, and routing to the single-country sibling, so nothing an agent needs to call it correctly is missing.

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 parameter already documents country names or ISO codes up to 5. The description merely restates 'one to five country names or ISO codes', adding nothing about format or edge cases beyond the schema. 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 (compare) and resource (travel advisories), and explicitly distinguishes itself from the sibling get_travel_advice by scoping itself to side-by-side multi-country comparison. An agent can route between the two without opening either schema.

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?

Gives concrete trigger phrases ('compare Mexico, Colombia and Peru', 'which of these countries has the highest advisory level?') and names the alternative tool (get_travel_advice) plus the condition that selects it (full text of one country). Explicit when-to-use and when-not-to-use.

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