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

The annotations mark this as non-read-only and non-idempotent, but the description adds substantial context beyond them: nothing is secured until payment, the tool returns a payment link, and deposit balance rules differ between private and shared tours. This is meaningful behavioral disclosure about the mutation's real-world effect.

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?

Four sentences with clear front-loading: first the action and return type, then the strict prerequisites, then the payment nuance. Every sentence adds necessary operational detail without repetition or filler.

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 complex 15-parameter mutation tool with no output schema, the description supplies the critical missing context: required prerequisites, the payment-link return format, the fact that payment is not automatic, and deposit handling by tour type. Parameter-level details are fully covered by the schema, so nothing an agent needs in order to call this correctly is absent.

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%, so the schema already documents all 15 parameters, establishing a baseline of 3. The description goes further by explaining deposit availability and the balance logistics for private versus shared tours, adding policy-level meaning to the payment parameter that the schema does not capture.

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 and resource ('Create a booking for a tour') and the output ('secure payment page for the traveller'). It distinguishes itself from siblings by naming the required prerequisite check_availability and by focusing on tour bookings rather than transfers (book_transfer) or searches.

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 states the two preconditions: only after check_availability and after the traveller has explicitly approved the restated tour, date, party, total and payment. It also explains the payment choices and their practical consequences, leaving no ambiguity about when this tool should be invoked.

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