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

Far exceeds the readOnly/idempotent annotations: it explains that null price_day/total_eur is normal and must not be reported as unavailable, distinguishes instant vs. owner-confirmed bookings, clarifies similar_model class guarantees, mandates verbatim booking_link, and forbids inventing phone/address/plate. This is unusually rich behavioral guidance.

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-loaded purpose sentence followed by clearly labelled PRICE and GOLDEN LINK RULE blocks, which is easy to scan. Minor redundancy: the 'null price is normal, not a failure' point is made twice, once in the intro and again in PRICE.

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?

Despite an output schema existing, the description explains the semantics of each returned field (available, days, price_day, total_eur, price_note, booking_link) plus booking-confirmation and privacy constraints. Nothing needed to call or interpret this tool 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 coverage is 67% and already documents the YYYY-MM-DD formats and maxItems 10. The description restates the 'up to 10 cars' cap and date framing but adds no new meaning about what vehicle_ids are or where to obtain them. Baseline 3 for a mostly self-documenting schema.

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 ('check availability and total price of up to 10 cars') with explicit scope (pickup/return dates) and enumerates the returned fields. It is clearly distinct from generic siblings like check_availability, though it never names a sibling to route against.

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?

Implies the tool is used to price/verify a set of vehicle_ids before booking, and the GOLDEN LINK rule hints at the booking flow that follows, but there is no explicit 'use this when / not when' or named alternative (e.g. search_vehicles first). Usage context 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.