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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely non-obvious behavior: a hard cap of 10 results, newest-first ordering, and the sign-in requirement. It omits edge behavior such as what happens if the person is not signed in or has zero trips.

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 short sentences, front-loaded with the result set and scope, followed by the auth prerequisite. Every phrase carries information — the cap, ordering, returned fields, and sign-in requirement — with no padding.

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 zero parameters, an output schema available, and annotations covering safety, the description is nearly complete: scope, ordering, fields and auth are all stated. The remaining gap is failure/empty-state behavior and any distinction from trip_status, which an agent would still have to guess.

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?

The tool takes no parameters and the schema is empty, so there is nothing for the description to disambiguate. The baseline of 4 applies; the description correctly avoids inventing options like pagination or filtering that the schema does not support.

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 names a specific resource and scope: the signed-in account's 10 most recent trips, newest first, with the exact fields returned (title, cities, dates, status, link). It does not, however, distinguish itself from the sibling trip_status or plan_trip, so an agent must infer the boundary between listing trips and querying one trip's status.

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 only implied by the auth prerequisite ("Needs the person to be signed in to AlgoTrips"). The description never says when to prefer this over trip_status for a single trip or plan_trip for creating one, so the routing decision with siblings is left to the agent.

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