lookup_regions

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

No annotations, but description covers dual behavior and an edge case. Output schema handles return format. Could add details like case sensitivity or language expectations.

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?

Two sentences plus a short note, no wasted words. Main purpose is front-loaded.

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?

Handles core behavior and a key edge case. Output schema exists for return values. Minor missing: case sensitivity or language hints.

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 has 100% coverage with description 'Optional region/oblast name to resolve'. The description adds that omission lists all, making the parameter's role fully clear.

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?

Description clearly states the tool lists all regions or resolves a name to an ID, using specific verb 'list' and 'resolve'. It distinguishes from sibling tools like lookup_cities by noting the Kyi city nuance.

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?

Explicitly says when to use (list or resolve) and gives a detailed note on how not to use it for Kyiv city, directing to lookup_cities/search_used_cars instead.

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