bus_line_info

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

With no annotations at all, the description carries the full burden and does real work: it discloses the free-text fallback (non-exact input lists matching lines rather than erroring), explains that trips_today = 0 means the line does not run today, and warns about past-midnight times written as '24:30'. It doesn't cover behavior on zero matches or result-set size limits.

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?

Front-loaded with the core purpose and the returned fields, then usage examples, then a compact Args block. Every line carries information the agent would not otherwise have; nothing is filler.

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?

An output schema exists, so return values needn't be spelled out, and the description instead spends its budget on edge cases the schema can't express (seasonal/weekday-only lines, midnight rollover, free-text fallback). For a 2-parameter lookup tool this is complete.

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 0%, so the description must compensate and does: 'line' is documented as either a 4-digit number or free text matched against line names, with the divergent behavior for each case, and 'include_stops' is documented as listing every stop id+name in order per direction. This adds meaning well beyond the bare string/boolean types in the schema.

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 opens with a specific verb+resource ('Details of a Carris Metropolitana line') and enumerates the concrete fields returned (name, route ends, directions, municipalities). The follow-up examples ('where does line 4715 go?') make it unmistakable versus siblings like bus_find_stops or bus_next_arrivals.

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 gives clear use cases and even routes an internal decision ('include_stops=True' to check whether a line passes a stop). What it lacks is an explicit exclusion naming the sibling to use instead for stop lookup or arrival times, so the agent must infer that boundary from the sibling names.

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