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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely new behavioral context beyond that: the bookable catalog is fetched live from the provider on every call, and booked entries echo the exact post-margin price charged at attach 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?

Well front-loaded with a one-line overview followed by scannable sections. It is somewhat long for a single-parameter read endpoint, and the 'Key Features' bullets partly restate the Overview and 'What You Get' sections (read-only, consistent pricing), which costs a point.

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 carries the burden of explaining the return shape, and it does so explicitly (groups with post-margin prices and encoded serviceIds, bookedServices, expiresAt). Nothing needed to call or interpret the response is missing.

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% for the single parameter, so the baseline is 3. The description adds value by specifying that bookingId goes in the URL path and that it originates from POST /flights/bookings, which the schema alone does not say.

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 (retrieve) and resource (ancillary services for a flight booking) and precisely delineates scope as both already-booked services and the live bookable catalog. This distinguishes it from the closely named sibling get_flights_bookings_bookingid, which returns the booking itself rather than its service catalog.

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 'When to Use' section gives three concrete scenarios (post-booking upsell, booking management, availability refresh) that tell an agent exactly when this endpoint applies, and the closing note rules out a use case (attaching services is not yet supported). It does not name a sibling alternative to route to, which keeps it 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.