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

Goes well past the annotations: discloses the persistence side effect (trip saved, kept 30 days, nothing booked or paid), hard limits (6 travellers, 60 nights, 5 places), that flight fares are estimates in this build, and the price-labelling scheme (live/estimate/official). This is exactly the context an agent needs before a non-readOnly, non-idempotent call.

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?

A single dense paragraph, but it is front-loaded with purpose and then side effects, limits and return shape in a sensible order. Nearly every clause carries information; only the price-label taxonomy is slightly verbose.

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?

No output schema exists, and the description compensates well by describing the return: up to six options, Safe Trip Total, route, price labels, booking link, and a 'building' status with trip id. It doesn't address repeated-call/idempotency behavior, which is the remaining gap for a write tool.

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?

With 70% schema description coverage, the schema already carries most parameter meaning. The description reinforces constraints (budget is total home-to-home, 6 travellers, 60 nights, 5 places) but adds nothing about pace, dining, interests, tripFocus, or the 'surprise' destination semantics beyond what the schema states.

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 ('Plans a whole trip, home to home, against the traveller's total budget') and enumerates the covered components (flights, stays, transfers, activities, visas, daily costs). This clearly separates it from the sibling read/lookup tools (get_trip, get_day_plan) and item-level tools (swap_trip_item).

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 opening ('For a request to plan a trip with a budget') gives a usage trigger, and the 'building' status note implies a follow-up via get_trip. However, no explicit when-not guidance or routing to siblings like best_time_to_visit or check_entry_requirements is given.

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