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

Annotations already declare the tool as readOnly, idempotent, and non-destructive. The description adds no extra behavioral context such as whether it returns a list, handles no-slot cases, or whether it reserves anything. It is consistent with annotations but does not enrich them.

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 a single, front-loaded sentence with no redundant words. It conveys the action, resource, and key constraints efficiently.

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 simplicity of the tool and lack of an output schema, the description covers the main scenario well. However, it does not explicitly state the return format (list of slots vs. boolean), which would be valuable in the absence of an output schema. Still, it is mostly adequate for an availability check.

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 covers all three parameters with descriptions (slug, serviceId, date format). The description does not add further parameter-level detail beyond the schema, such as where serviceId comes from or date format specifics. Therefore, the schema carries the semantic weight.

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 'Check' with a clear resource 'open appointment slots' and specifies the parameters (service, business, date). It clearly distinguishes this from sibling tools like 'book_appointment' by indicating it is a pre-booking availability check.

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 implies usage when one needs to view open slots for a service at a business on a date, but it does not explicitly state when to use this over alternatives like 'book_appointment' or 'get_business'. No exclusions or prerequisites are mentioned, so guidance is only implied.

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