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

Annotations already declare readOnlyHint and idempotentHint, so the description does not need to repeat safety. It adds useful scope and output context ('they own or have joined, with dates and whether they own it'), but does not disclose additional behavior such as ordering, pagination, or what happens with an empty trip list.

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?

The description is a single, well-structured sentence that immediately states the action, scope, and key output fields. It contains no filler or redundancy.

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 simple, parameterless list tool, the description is fully complete: it identifies what is listed, whose journeys are included, and what information is returned. No output schema exists, but the description covers the essential return-value expectations at the appropriate level of 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?

The tool has zero parameters, and the schema already fully reflects this with an empty properties object. The description therefore has no parameter semantics to clarify, and a baseline of 4 is appropriate.

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 uses a specific verb ('List') and identifies the resource ('the user's trips (journeys) they own or have joined'), plus the key output details (dates and ownership). This clearly distinguishes it from sibling tools like get_journey or list_journey_members.

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 description implies the usage context: it is for listing all of the user's journeys rather than a single journey or members. However, it does not explicitly mention alternatives or provide exclusion guidance, so the usage guidance remains implicit rather than explicit.

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