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

With no annotations, the description carries the full burden. The verb 'List' implies a read-only operation, and the referenced fields provide some context, but the description does not disclose authentication requirements, whether the list is static or dynamic, or any other behavioral caveats. It is adequate but not rich.

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 short, dense sentences. The first states the action and output fields; the second provides a cross-reference to get_incidents. No filler or redundancy.

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?

Since there is no output schema, the description compensates by listing the returned fields and explaining how to use them with get_incidents. Given the tool has no parameters and a simple list behavior, this is nearly complete, though it stops short of detailing formats like bbox structure.

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 input schema has zero properties, so there are no parameters to explain. Per the rubric, a zero-parameter tool gets a baseline of 4; the description adds no parameter semantics because none are needed.

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 uses a specific verb and resource: 'List CityAlert focus regions,' and enumerates the returned fields (key, label, center, zoom, bbox). This clearly distinguishes it from sibling tools like get_incidents, which return incident data rather than region metadata.

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 sentence 'Use region keys with get_incidents' explicitly tells the agent when to use this tool (to obtain region keys) and how the output feeds another sibling. It does not explicitly mention when not to use it, but for a zero-parameter list tool this is sufficient context.

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