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

Annotations carry only readOnlyHint=false, so the description bears most of the burden and delivers real substance: no payment is taken through the tool, the return is a secure checkout_url, an agent_key must be obtained from an admin, and terms_accepted must not be set without an explicit customer yes. It omits what happens on failure, whether bookings can be amended/cancelled, or any rate limits.

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?

Three tight sentences with zero waste, front-loaded with what the tool does before moving to the return value and the credential requirement. Every sentence earns its place.

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 22-parameter write tool with no output schema, the description supplies the critical agent-facing context (auth requirement, checkout_url return, payment never handled here, terms gate). It stops short of covering error behavior and the pricing/optional-parameter interactions, but the schema handles most field-level detail.

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 77%, but the description adds meaning the schema lacks: it explains the agent_key provenance (contact admin@cgctransfers.com.au) and enforces the correct semantics of terms_accepted. It does not touch other nuanced fields such as seat_qty vs child_seats or the return_date/return_time pairing.

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?

The description opens with a specific verb+resource ("Lodge a booking"), and the mechanism is concrete: it returns a checkout_url for payment. It does not explicitly distinguish itself from siblings (check_availability, get_quote, get_service_info), which is the only thing keeping it from a 5.

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?

Usage is implied through the workflow (get a quote/availability, then lodge), and it tells the agent to hand the checkout_url to the customer rather than pay. However, it never states when to prefer this over get_quote or check_availability, nor any prerequisites such as confirming availability first.

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