Public transport timetable

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

Annotations already declare read-only, non-destructive, idempotent behavior, so the description only needs to add value beyond those hints. It adds that the data is 'official timetable data' and that the tool supports two modes, which is useful context about the result nature. No contradiction with 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?

One sentence with no filler; the geographic scope, data source, and dual modes are front-loaded. It is as concise as possible while giving the essential purpose.

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?

For a read-only query tool with an output schema and well-documented optional parameters, the description is nearly complete: it names the domain, scope, and modes. A small gap is not explicitly instructing when to use 'connections' vs 'next departures', but the schema's destination parameter covers this.

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 80%, so the schema carries most parameter documentation; the description does not repeat or add parameter-level detail. The one undocumented parameter (limit) is adequately constrained by min/max/default in the schema, so this is acceptable.

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 names a specific resource ('Swiss public transport') and the two main operations ('connections or next departures'), making the tool's purpose immediately recognizable. It lacks an explicit verb such as 'search' or 'get' and does not explicitly contrast with sibling tools, but no other sibling covers public transport.

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?

The description implies when to use the tool: whenever a user needs Swiss public transport connections or a departure board. It does not state exclusions or compare with alternatives such as swiss_place_info or swiss_coverage, so usage guidance is inferred rather than explicit.

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