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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, and the description adds useful behavioral context: simulated crowd is excluded, predictions are unofficial and may be wrong, and station screens are authoritative. It does not cover return format or pagination, but the added caveats are meaningful beyond the annotations.

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 short and front-loads the core output. 'Read only' is redundant with annotations, but the remaining sentences about exclusion criteria and official sources earn their place.

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 and only 50% parameter description coverage, the description should do more to explain the return shape and the role of the 'days' parameter. It adequately conveys the metric and caveats but is incomplete for an agent needing to call it correctly.

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 50%, with 'station' documented in the schema but 'days' undocumented. The description does not mention either parameter, so it does not clarify the meaning of the days window or how station affects the accuracy breakdown, leaving a notable gap for the undocumented parameter.

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 states a specific analytical output: measured accuracy by minutes before release, with sample sizes. It clearly distinguishes the tool from train/departure/station lookup siblings by focusing on prediction reliability, though it does not explicitly name alternatives.

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?

It provides a data-quality warning about unofficial predictions and official station screens, but gives no explicit guidance on when to call this tool versus siblings like get_departures or get_train. There are no exclusions or recommended contexts beyond the caveat.

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