country_by_ip

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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so the safety and network-call profile is covered. The description adds only the upstream provider (country.is), which is mild context, and says nothing about rate limits, failure behavior, or response shape.

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?

One sentence, front-loaded with the operation and resource, no filler. It is arguably too terse for the amount of routing ambiguity in this sibling set, but nothing is wasted.

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 trivial one-parameter lookup with full annotations the description is serviceable, but with no output schema it never indicates whether the result is a country code, name, or object. That is a meaningful gap for an agent deciding how to consume the result.

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 'ip' parameter already documents the auto-detect fallback. The description adds nothing beyond the schema, so 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 and resource ('Detect country from an IP address') plus the backing service, so the agent knows exactly what it returns conceptually. It does not distinguish itself from adjacent siblings such as ip_lookup, ipinfo_lookup or ip_address_lookup, leaving the reader to infer the difference from names alone.

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?

No guidance on when to prefer this over ip_lookup, ipinfo_lookup or ip_address_lookup, and no mention that omitting the IP triggers auto-detect (that fact lives only in the schema). The agent must infer all routing decisions.

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