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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds real value beyond that by disclosing the shape of the payload (journey plus steps) and, importantly, that include_personal surfaces a private e-mail address, flagging privacy-sensitive data an agent should treat carefully. It does not state any permission or scoping requirements, which keeps it from 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?

Two sentences, front-loaded with the primary return shape, then the optional-field caveat. The trailing "GraphQL query journey" is the only near-waste, and even that gives an implementer a useful handle. Zero bloat overall.

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 no output schema present, the description carries the return-value burden and does so by naming the journey, its steps and their fields, plus the conditional personal e-mail. Combined with annotations covering safety, an agent has enough to call it correctly; only error behavior for an unknown id is left implicit.

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 description coverage is 100%, with both journey_id and include_personal documented in the schema, so the baseline is 3. The description's restatement of include_personal adds only the slight emphasis that the e-mail is "private" and "stored on the journey" – useful framing, but not meaning the schema omits.

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 opens with a specific verb-and-resource statement ("One journey by id") and enumerates the returned step fields (name, description, fixed start and due dates), so an agent can tell it apart from kiwihr_list_journeys without opening the schema. It stops short of naming the sibling it is not, which is the only thing separating a 4 from a 5.

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 the required journey_id: call this when you already have an id and need full detail. There is no explicit when-to-use, no when-not-to-use, and no signposting to kiwihr_list_journeys or kiwihr_list_journeys_templates as the way to obtain that id.

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