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

Annotations provide readOnlyHint=false and openWorldHint=true, and the description adds useful behavioral detail beyond those: it sends a 6-digit SMS code and requires prior customer consent. It would be stronger if it stated whether the slot is actually reserved at this point or only held, but the key side effects are disclosed.

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 three short sentences with no filler. It front-loads the primary action, then states the side effect, the critical precondition, and the return value. Every sentence contributes to correct usage.

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?

With nine parameters, no output schema, and sparse schema descriptions, the description covers the main behavioral contract but leaves gaps. It mentions the verificationToken return value and the terms precondition, yet it does not explain the overall booking lifecycle, what happens after verification, or the meaning of several required parameters. It is adequate but not fully complete for a tool of this complexity.

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 only 33%, so the description should compensate for undocumented parameters. It does not explain date, time, serviceIds, customerName, customerEmail, hairdresserId, or note. The only parameter-related behavior in the description is the termsAccepted precondition, which maps to the schema but adds little semantic value.

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 a specific verb and resource: 'Start a booking.' It further differentiates from sibling confirm_booking by explaining this step sends an SMS verification code and returns a verificationToken for the confirmation step, so an agent can identify the correct tool in the flow.

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 precondition: 'Call only after the customer explicitly agreed to the terms and privacy notice.' It also hints at sequencing by mentioning the token is for confirm_booking. It does not explicitly list exclusions or when-not-to-use alternatives, but the context is clear enough for correct usage.

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