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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false), yet the description adds real value: it enumerates cancellation-policy states (free/conditional/not cancellable), discloses the amend-option flag, and states the auth requirement ('Cotlet API key with access to this app'). This is meaningful context beyond the structured fields.

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 opening and second sentence redundantly restate the same payload ('participants ... voucher link' appears in both), wasting space. The when-to-use guidance is placed last rather than front-loaded, so structure is adequate but not tight.

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 no output schema, the description correctly carries the return-shape burden by naming date, time, participants, voucher link, and cancellation states. Auth requirements and the follow-up actions are also covered, leaving only minor gaps (no pagination/error behavior, though none is expected for a single-record fetch).

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 100% and the single booking_ref parameter is fully documented in the schema ('Booking Reference ID from list_bookings, e.g. ABC123456'). The description adds no syntax, format, or sourcing detail beyond that, so the baseline 3 applies.

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+resource ('One booking with participants, cancellation policy, amend option and voucher link') and clearly scopes it to a single record, distinguishing it from the sibling list_bookings as well as amend_booking/cancel_booking. An agent can tell exactly what it retrieves without opening the schema.

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?

Explicitly routes the agent: 'Check it before amend_booking or cancel_booking,' naming two concrete alternatives and the condition selecting them. It lacks any when-not guidance (e.g. vs list_bookings for bulk retrieval), so it stops just short of a 5.

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