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

Annotations already declare readOnly/openWorld/idempotent/non-destructive, so the safety profile is covered. The description adds what annotations cannot: the result is a link to a full roadbook the user can open, edit and share, and it discloses the conditional enrichment (holidays and visa deadlines only with a start_date, entry rules keyed to passports/residence/plates). No rate limits or failure modes are mentioned.

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 sentence with front-loaded purpose, followed by a short routing instruction; nothing is filler and every clause names a distinct output. It is long, but the length buys real coverage for a 17-parameter tool, though the mid-sentence enumeration could be split for faster scanning.

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 an output schema present and full schema coverage, the description only needs to convey scope, enrichment conditions and the returned artifact — all of which it does. Nothing an agent needs to decide and invoke this tool correctly 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 100%, so every one of the 17 parameters is already documented in the schema, including defaults and enums. The description only restates the waypoint count constraint and that passports/residence/plates drive entry rules, adding little beyond the structured data — baseline 3.

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?

Opens with a specific verb+resource+constraint ('Plan a road trip by campervan or car between 2-10 places') and then enumerates concrete outputs: distance, driving time, day-by-day plan, budget, per-country entry rules, 90/180 stays, LEZ/ZTL rules, holidays, plugs, checklist, shareable link. This is unmistakably distinct from every single-purpose sibling such as check_visa_rules or estimate_route_tolls.

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 closing sentence 'Use this first when the user describes a trip from A to B' gives explicit routing guidance relative to the narrower sibling tools. It does not state when NOT to use it (e.g. a single-country visa question should go to check_visa_rules), so it stops 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.