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

The description does not mention side effects or permissions, but the annotations already provide readOnlyHint and idempotentHint. It adds a caution about not using it for appointment proof, which is a useful behavioral note, but it does not go beyond what annotations already cover.

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 two sentences, efficiently combining purpose and usage guidance. It is well-structured with a positive statement followed by a negative constraint, with no unnecessary wording.

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 provides enough context for an agent to decide when to call the tool, what parameters to provide, and what outcome to expect (whether Johnson Bros. serves the area). It also differentiates from sibling tools like request_booking and get_availability.

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 includes 'zip' and 'town' without descriptions. The tool description clarifies that these refer to a Massachusetts ZIP code or town, giving them meaning and indicating they are alternative inputs. This adds value beyond the raw schema.

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's function: given a Massachusetts ZIP code or town, it checks whether Johnson Bros. serves that area. It uses a specific verb ('serves') and distinguishes itself from related tools like get_availability.

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?

It explicitly states when to use the tool (when a MA ZIP or town is provided to check service area) and when not to use it (not as proof of appointment availability), giving clear guidance relative to sibling tools.

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