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

readOnlyHint already covers the safety profile; the description adds genuinely new behavioral context, namely that results include a per-target justification and flag plans the account lacks. It does not describe pagination or ordering, but for a read-only listing that is a minor gap.

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, front-loaded with the core action and followed by the 'Answers:' framing of the use case. No filler, though the clause about missing plans is slightly dense and could be split.

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, the description carries return-value burden and does describe the three components of the response (list, rationale, missing plan). It is essentially complete for a single-parameter read tool, missing only ordering or empty-result behavior.

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?

Only one parameter with 100% schema coverage, where the schema already says 'Target id from chargerdojo_list_targets.' The description reinforces that filtering is by role and version of the target but adds no format or sourcing detail beyond the schema, so the baseline 3 applies.

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 ('List the charging journeys') plus a precise scope ('that can run against one target on this account'). The description also enumerates the extra outputs (why the target supports them, missing plan), which separates it from chargerdojo_list_journey_templates.

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?

'Answers: which journeys fit this endpoint, by its role and version' implies when the tool applies but never states exclusions or names the alternative to use for template listing or actual execution. It gives context rather than explicit routing.

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