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

With no annotations, the description carries the full burden. It is transparent about data limitations: explicitly notes there is no live vessel tracker and statuses reflect published information, not observed conditions. It also lists all output components, providing a clear behavioral contract.

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 quite long and repeats concepts (e.g., 'right now' and 'for today', 'published' and 'PUBLISHED'). While it is detailed and well-structured, the redundancy could be trimmed without losing clarity.

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?

Although there is no output schema, the description enumerates every major output component: sailings, statuses, next departure, check-in, route state, 30-day record, and bilingual notices. This gives a complete picture of the tool's results, though a formal output schema would be even more precise.

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?

The schema covers the single parameter (route) with 100% coverage, and the description further clarifies valid values ('vieques, culebra, catano') and behavior ('Omit for all three'). This leaves no ambiguity about the parameter's meaning or usage.

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 the tool returns ferry status for specific Puerto Rico routes, with a clear verb ('returns') and resource ('each route's published sailings'). It distinguishes itself from sibling tools by focusing on ferry operations, which are unique among the news, weather, and municipal tools.

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 details what information is returned (statuses, next departure, check-in time, 30-day record, notices) and that an optional route parameter can be used. It does not explicitly state when to use this tool versus a sibling, but the subject matter is sufficiently distinct from siblings to make the appropriate context clear.

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