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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety and idempotency are covered. The description adds the shape of the result (capital, population, currency, languages, neighbors), which is genuinely useful, but says nothing about behavior for unknown or ambiguous names (e.g., partial matches, misspellings) or data freshness.

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?

Three short sentences, front-loaded with the operation and the accepted input format, then the return payload, then usage. No wasted clauses, though the trailing usage sentence is thin enough that it borders on 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?

A single-parameter lookup with rich annotations and an output schema is fully specified here; the agent needs nothing more to invoke it correctly. The description does spend words listing return fields that the output schema already defines, which is a minor redundancy rather than a gap.

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 coverage is 100% and the schema already documents the single parameter as 'Country name or ISO 3166-1 alpha-2/alpha-3 code'. The description's inline examples ('US', 'FR') reinforce the accepted formats but add little beyond what the schema and its examples array already supply, so the baseline of 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 and resource (get country information) plus the accepted lookup key (name or ISO code) and enumerates the returned fields, so the agent knows exactly what comes back. It does not explicitly distinguish itself from lookalike siblings such as geo_geocode or geo_get_timezone, but the 'country facts' framing makes the distinction inferable.

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 final clause 'Use for regional context or facts' gives implied usage context but no explicit when-not-to-use condition and names no alternative tool. An agent working with geo_geocode or geo_get_timezone gets no routing signal from this definition.

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