Predicciones de llegada

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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds the data source (iBus + RED web) which is useful context, but doesn't explain the output format despite having an output schema, nor the live/real-time nature's implications (staleness, caching, polling behavior). With an output schema present, some burden is relieved, but the description could note that results are time-sensitive predictions.

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?

The description is compact at two sentences, front-loaded with the core function. The usage hint is efficiently integrated. It's lean without being under-specified, though a bit more parameter detail would improve the score.

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?

The tool has 2 parameters (1 required), an output schema, and readOnly annotations. For a simple read-only arrival prediction lookup, the description covers the core purpose and usage sequence. However, with 0% schema coverage and no parameter documentation, the description is somewhat thin for a tool with an output schema that could contain complex prediction data. It's adequate but could elaborate on what 'service' selects and the nature of returned predictions.

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 for parameter meaning. However, the description does not explain what 'stop_code' means, what format it should be in (numeric? string?), or what the 'service' parameter does. The description mentions resolving the code via search_stops but does not define the parameter types or expected values beyond what the schema name implies.

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 clearly states 'Predicciones de llegada en tiempo real para un paradero' (real-time arrival predictions for a stop) with a specific verb in Spanish. It identifies the data source (iBus + RED web) and differentiates from siblings by focusing on arrival predictions for a resolved stop code. It doesn't explicitly name a sibling alternative but the context of using after search_stops helps.

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 explicitly states when to use this tool: 'Usar después de resolver el código con search_stops' (use after resolving the code with search_stops). This provides clear sequencing guidance and ties it to the search_stops sibling, which is the prerequisite. It gives actionable usage context.

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