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

With no annotations, the description carries the burden of behavioral disclosure. It adds useful details beyond the schema, such as the slug format examples and US-specific area code behavior. But it does not mention edge cases, error handling, or whether any side effects exist, though the tool appears to be a read operation.

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 sentences, each earning its place: the output content, the downstream usage, and the slug format. Information is front-loaded and there is no filler or repetition.

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?

The description explains the returned data and slug conventions, which is helpful for a two-parameter tool with no output schema. However, the required 'country' parameter is not defined, and error or invalid-input behavior is absent, leaving meaningful gaps for correct invocation.

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?

The schema documents only 'region' as 'Region slug' (50% coverage). The description enriches the region parameter with lowercase-hyphenated format and examples, but leaves the 'country' parameter completely unspecified beyond an implicit US reference. This is partial compensation for the coverage gap.

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 defines the tool as returning a region (state, région, wilaya, governorate) with its subdivisions, slugs, postal codes, and area codes for US states. It also references get_group and get_place, helping distinguish it from sibling tools like area_code_lookup and search_places.

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 gives a clear downstream usage instruction ('Use the slugs it returns to call get_group or get_place') and implies the tool is for retrieving region-level data. However, it does not explicitly state when to choose this tool over siblings like area_code_lookup, nor does it provide exclusions or alternative conditions.

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