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

Annotations already cover readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is disclosed. The description adds valuable context beyond that: it specifies the return data is customer-facing and that it never includes customer data, which is a privacy-related behavioral trait not present in the annotations. This goes a notch beyond the minimum, hence a 4.

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 with no filler. It front-loads the primary use case and immediately states the exclusion, making it easy to parse. Every word earns its place.

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?

While the output schema covers return format and annotations cover safety, the description fails to explain what the parameters actually do. The agent cannot correctly specify 'days' or 'start_date' without guessing semantics. For a tool with no required parameters and a clear output schema, the missing parameter context leaves a significant gap in actionable completeness.

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% and the description provides zero explanation of the parameters (days, start_date, time_preference). The tool's description does not add any meaning beyond the raw schema, which only gives names and types. With 0% coverage, the description carries the full burden of explaining parameter usage, and it fails to do so.

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 states a specific verb ('get'), resource ('live Johnson Bros. appointment availability'), and explicitly scopes the return to 'customer-facing arrival windows and capacity only, never customer data'. It clearly differentiates from the sibling tools 'request_booking' and 'confirm_booking' by stating what it is not for, so an agent can select it correctly.

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 an explicit condition for use ('when the user wants live appointment availability') and an explicit exclusion with named alternatives ('Do not use it to promise or create an appointment; use request_booking and confirm_booking for that'). This provides clear routing guidance with no ambiguity.

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