Arrival board

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

Annotations already declare the operation read-only and idempotent, so the description does not need to repeat those. It adds useful context by calling the board 'live' and clarifying that direction is interpreted as origin, which helps distinguish arrival semantics from departures. Beyond that, no additional behavioral traits such as pagination or data freshness are disclosed.

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 concise sentence with no filler and is easy to parse. However, the brevity comes at the cost of missing parameter and usage details, so it is under-specified rather than optimally concise.

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 five parameters and a low schema coverage, the description should provide more context than it does. The pointer to db_departures helps, but the description still leaves key invocation details such as time window, format, rail-only filtering, and when-to-use semantics to be inferred.

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 only 40%, and the description does not compensate by explaining minutes, format, rail_only, or station. The phrase 'same shape as db_departures' may hint at output structure, but it adds little meaning to the actual parameters and leaves several fields underspecified.

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 clearly identifies the tool as a live arrival board and distinguishes it from the sibling db_departures by adding 'direction = origin'. However, it relies on a noun phrase rather than a specific action verb like 'list' or 'retrieve', so it is clear but not maximally explicit.

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?

There is no guidance on when to use this tool versus alternatives. The reference to db_departures implies a relationship, but it does not state when arrivals are appropriate, when departures should be used, or any exclusions.

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