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

Annotations already declare readOnlyHint=true, so the tool's safe, non-mutating nature is covered. The description adds useful context: 'real-time' and a fixed limit of 'next 10 open slots' with start timestamps. However, it doesn't disclose behavior on no available slots, invalid provider, or pagination, which are gaps beyond the annotation's safety coverage.

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 concise sentences with no filler. The primary purpose ('Real-time availability for ONE specific provider') is front-loaded, and the return behavior is stated in the second sentence. Every word earns its place; this is appropriately sized for a simple lookup tool.

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?

For a tool with three required parameters and no output schema, the description omits critical context: it does not explain that state and appointment_type are needed, nor what the numeric codes represent, nor error behavior when no slots exist. Since there is no output schema, the description also fails to describe the structure of returned slots beyond 'start timestamps'. The tool is simple, but the description leaves too much for the agent to infer.

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 description coverage is 0%, so the description must compensate for parameter meaning, but it barely does. It only implies provider_id via 'ONE specific provider' and gives no indication of what state or appointment_type (the numeric enum values) mean. Field names and enums are the only signal, leaving the agent to guess at the semantics of required parameters.

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?

States a specific verb ('returns availability') and resource ('slots for ONE specific provider'), clearly distinguishing it from sibling tools like find_provider (search) and book_appointment (booking). The phrase 'ONE specific provider' explicitly narrows the scope, so an agent can immediately tell it apart from a provider-search tool.

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 this tool is for checking slots of a known provider (via 'ONE specific provider') but does not explicitly state when to use it instead of siblings. It doesn't mention that find_provider should be used to locate a provider first, or that book_appointment follows this check. Usage context is implied but not explicit.

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