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

Annotations already declare destructiveHint=true and idempotentHint=true, yet the description adds real value: it discloses the 'every current trip_city_id exactly once' validation requirement and the side effect that the first city drives the automatic cover image. That side-effect disclosure goes meaningfully beyond structured data.

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?

Two tight sentences with the core operation front-loaded and the constraint and side effect following. Zero filler; every clause 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 two-parameter mutation whose annotations already carry the safety profile, the description covers the operation, the enumeration constraint, and a notable side effect. It could say what happens on an incomplete/invalid list, but nothing essential for correct invocation 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 the baseline is 3, but the description reinforces the schema's 'Complete ordered list' wording with the sharper 'exactly once' constraint, clarifying that this is a full replacement rather than a delta. This adds a validation nuance beyond the schema text.

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 ('Replace the trip city order') and adds the key constraint that every current trip_city_id is used exactly once, which implicitly separates it from trip_city_add/remove/update. It does not explicitly name a sibling, but the operation is unambiguous to an agent.

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 by 'Replace the trip city order' and the required full enumeration, but there is no explicit when-to-use vs alternatives guidance and no exclusions. Adequate minimum viability for a reorder operation, with the constraint carrying most of the routing weight.

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