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

Annotations already establish the read-only, closed-world, non-destructive profile, and the description adds real value on top: the departureAt/arrivalAt vs departureDate/arrivalDate output/input naming mismatch is a concrete error-avoidance detail. It stops short of disclosing anything about failure modes (e.g., not-found or ownership scoping behavior), so not a 5.

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?

Purpose is front-loaded in the first sentence, followed by workflow guidance, with domain rules last. It is slightly overloaded with journey-splitting rules (airside connections, immigration) that arguably belong in the guide tool rather than a getter definition.

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, return values needn't be enumerated, yet the description usefully flags the leg time field names. Nothing blocking is missing, though domain semantics around journey splitting could be deferred to the referenced guide.

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?

Single required parameter at 100% schema coverage, so the schema already carries the semantics. The description only implies 'one owned journey' scoping and adds no syntax or format guidance for id beyond what the schema provides.

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 ('Get one owned journey by id') plus the returned shape (presence stamps, ordered legs), which cleanly separates it from list_journeys and get_journey_review. An agent can identify it without opening the schema.

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?

Explicitly names the downstream use case ('call this before update_journey so a replace-all route update preserves per-leg details') and names an alternative entry point (get_tripledger_guide) for unfamiliar callers. That is when-to-use plus routing in one place.

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