Recorridos directos entre dos puntos

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the read-only safety profile is covered. The description adds the key behavioral fact that this tool does not handle transfers (only direct routes). However, it doesn't clarify how 'direct' is defined (geographic proximity? same line?) or what happens with routing variants, which would add useful context.

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, completely front-loaded with the primary purpose then the exclusion with an alternative. No wasted words.

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?

This is a moderately simple tool (5 params, all primitive numbers) with a good output schema and solid annotations. The description captures the core behavior (direct routes only) and directs to the transfer-planning sibling. Some minor gaps remain around radius_km semantics, but given the structural richness elsewhere, this is reasonably 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%, meaning the description adds no parameter explanations. Of the 5 parameters, only radius_km has a title/default hint in the schema; the four required lat/long parameters are self-explanatory by name but the description gives no semantic context for radius_km (search radius for stops at endpoints?) or for how the coordinates relate to stops. The description provides zero compensation for the 0% coverage gap.

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 says 'Sugerir recorridos directos que conecten dos puntos' (Suggest direct routes connecting two points). The verb is clear and the resource (direct routes between two points) is specified. It doesn't explicitly distinguish from all sibling tools, but the 'direct' qualifier does separate it from plan_journey which is named.

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 states 'No planifica transbordos; para eso usar plan_journey' (Does not plan transfers; for that use plan_journey). This explicitly names an alternative tool and states when NOT to use this tool. It provides a clear exclusion with a named alternative.

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