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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: the auth requirement ('Needs the user's Cotlet API key with access to this app') and the full shape of the returned record, which matters since there is no output schema.

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?

Front-loads the resource well, but the list 'services, address, provider, price and job length adjustments, notes and charges' is restated almost verbatim in the second sentence, which wastes space. The opening fragment 'BookingKoala: Full booking:' is also awkward.

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 read-only single-record tool with no output schema, the description competently carries the return-value burden and notes the required API key access. It is complete enough to call correctly, with only minor gaps (e.g., behavior if the booking_id is not found).

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 100% with a single required booking_id, and the schema itself documents it as 'Booking ID from list_bookings.' The description adds nothing about the parameter, so the baseline 3 is appropriate when the schema does all the work.

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 (get a booking) and enumerates exactly what the record contains (services, address, provider/team, price and job length adjustments, notes, charges). The 'Returns one booking' phrasing distinguishes it from the sibling list_bookings, so an agent can select it 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?

Gives clear when-to-use guidance: 'Use it before changing a booking so your agent sees its current state,' which situates it as a pre-mutation read. It does not name a specific alternative or state exclusions, so it falls short of the explicit when/when-not/alternative pattern.

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