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

Annotations already cover read-only/idempotent/non-destructive, yet the description adds substantial behavioral detail: the return value (ISO 3166-1 alpha-3 code and name), the failure modes (not-rated places like Bermuda or Puerto Rico with a reason; US states flagged separately), and a prompt-injection guard for quoted text.

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-loads the core purpose in the first sentence and orders the rest logically (inputs, outputs, usage, safety). Slightly dense, but every sentence carries distinct information.

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?

There is no output schema, so the description must describe returns — and it does, including the three distinct outcome shapes. Inputs, usage, outputs, and safety are all covered for a single-parameter tool.

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 parameter already has examples, so the baseline is 3. The description adds genuine meaning by enumerating accepted input forms: country/territory names in English or another major European language, everyday names like England or Holland, or a raw code.

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 precise verb+resource ('Turn a place name into the code the other tools use') and defines the resolution role clearly enough to separate it from get_country, get_state, and list_countries. An agent knows this is the lookup/resolution entry point.

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 explicit when-to-use guidance: 'Use it first when you are not sure of the code.' It does not name a specific alternative or when-not-to-use case, but the routing intent is unambiguous.

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