get_supported_subdivisions

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

With no annotations, the description carries full burden for behavioral disclosure. It notes case-sensitivity, return value structure, and raises ValueError for unknown countries. It does not mention performance or rate limits, but for a simple lookup tool, this is largely sufficient.

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?

The description is well-structured with sections: main purpose, usage guidance, important note, example, formal Args/Returns/Raises. It is concise yet comprehensive, with no redundant sentences.

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?

Given the tool's simplicity (single parameter, straightforward lookup), the description fully covers purpose, usage, parameter semantics, return format, and error handling. The inline output schema compensates for the missing structured output schema.

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 0%, so description must add meaning. It specifies that `country` is an ISO 3166-1 alpha-2 code, case-insensitive, and normalized to uppercase. This is valuable context beyond the bare schema type.

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?

The description clearly states the tool lists subdivision codes and aliases for a country's holiday calendar. It specifies the action (list), resource (subdivision codes/aliases), and scope (per country). It distinguishes from siblings by mentioning its role in discovering valid `subdiv` values for other country-aware holiday tools.

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 description explicitly advises using this tool before calling other country-aware tools like `is_business_day`, `list_holidays`, and `next_business_day`. It provides guidance on case sensitivity and normalization of subdivision codes, and includes an example for clarity.

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