bus_find_stops

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

No annotations are supplied, so the description carries the full burden and does well: it discloses distance-sorted results, result contents (lines serving each stop), accent/case-insensitive matching requiring all words, that a 6-digit id is accepted as a query, and the conditional radius default. It omits only edge behavior such as what is returned when nothing matches or when lat/lon is supplied without a query and no stops fall in range.

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?

Purpose and the 'use this first' routing rule are front-loaded, then a compact Args block gives per-parameter detail. The Lisbon/Carris caveat is the only aside, and it earns its place by preventing a false-negative conclusion.

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 need not be described, and the description still notes that results include serving lines. With five optional parameters, no annotations, and a coordinate-based search, everything an agent needs to call this correctly is present.

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%, and the description fully compensates: every one of the five parameters gets concrete semantics (matching rules, WGS84, default 500 m only when no query, default 10 / max 50). The conditional interaction between radius_m default and the presence of query is information available nowhere 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 first sentence names a specific verb and resource (find bus stops) and scopes it to a named operator, Carris Metropolitana. It is immediately distinguishable from siblings like bus_next_arrivals and bus_line_info, which are explicitly framed as downstream consumers of this tool's output.

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?

Explicitly states 'Use this first whenever the user names a place, street, station or gives a location', and names the dependent tool (bus_next_arrivals) that consumes the returned stop_id. It also adds a genuine scope exclusion — Lisbon city buses are Carris, not covered here — which prevents a predictable misfire.

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