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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, and the description is consistent with them while adding real context: an optional start is validated against the live schedule, and no slot is reserved and no message is sent. It stops short of describing rate limits, caching, or failure behavior when the live check rejects the start time.

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?

Three short sentences, zero filler, with the deliverable listed first and the boundary conditions after. Every clause carries information an agent needs.

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?

An output schema exists, so return values need no explanation, and annotations carry the safety profile; the description still covers content and the live-schedule validation. Only the timezone parameter and the interaction between session_type and cancellation rules remain thin for a 4-parameter tool.

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 coverage is only 25% – only session_type is documented in-schema. The description partially compensates by naming language (locale), an 'optional selected start' (start_at), and tying cancellation rules implicitly to session type, but timezone and the ru/en locale values are unaddressed in both places.

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 concrete verb ('Prepare') with the specific payload it assembles: price, language, cancellation rules, and a booking-form link. That distinguishes it from the retrieval siblings (get_services_and_pricing, get_available_slots), though no sibling is named explicitly and the word 'handoff' is never unpacked.

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?

'Does not reserve a slot or send a message' clarifies scope and implies this is a pre-booking step, but it never says when to reach for it instead of get_available_slots or get_services_and_pricing, nor what precondition (e.g. a chosen session_type) is expected. Usage is inferable rather than stated.

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