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

Annotations already declare readOnly, idempotent, non-destructive, open-world behavior, so the safety profile is covered. The description does add one real behavioral detail — that the service_id must be an exact, cached value rather than a fuzzy or live lookup — which is useful context. It still says nothing about data freshness, failure modes when the id is not cached, or what the response contains.

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 short sentences, front-loaded with the key inputs, so there is no padding. However, the second sentence is opaque enough that it consumes space without conveying actionable information, weakening the otherwise tight structure.

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?

There is no output schema, so the description carries the burden of explaining the return value — yet 'qualified platform sentence' is never defined, leaving the agent unsure what it will receive. Combined with an entirely undocumented service_id parameter, the definition is under-specified for a lookup tool.

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 coverage is 50%: station is well documented with a pointer to list_stations, while service_id has no schema description at all. The description partially compensates by stating service_id must be an exact cached value, which helps the agent know not to pass an arbitrary or approximate id. It does not explain the expected id format or where a cached id comes from.

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?

It names a resource (platform) and the two things it keys on (station, exact cached service_id), so the agent grasps it returns platform information for a specific service. But 'qualified platform sentence' is unexplained jargon, and the second sentence ('Plans and history are never reports') does not clarify what output the tool actually produces. It is not a tautology of the name, but the purpose is only partly legible.

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 pick this over get_departures or next_train, and no stated prerequisites beyond the schema's pointer to list_stations for the station value. The phrase about plans and history being 'never reports' hints at a scope exclusion, but it is too cryptic to function as usable when-not guidance.

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