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

The annotations provide only a title, so the description carries the transparency burden. It discloses that data includes 'now and for the days ahead', which conveys a forecast scope, and lists the provided metrics. However, it does not mention edge case behavior, data source, or any caveats, leaving some behavioral aspects undeclared. Since it is a read-only weather tool, the description is adequate but not extensive.

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?

A single, well-structured sentence delivers all essential information—resource, location type, data types, and temporal scope—without any filler or redundancy. It is concise yet informative.

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 is simple (3 parameters, no output schema) and the description explains the returned data types and time range, which is sufficient for basic use. It could be more complete by specifying units (e.g., meters, seconds, degrees Celsius) or noting data limitations, but given the low complexity and full schema coverage, it offers a complete enough picture.

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 input schema already covers all three parameters with descriptive text (lat/lon and days default 3), so the description adds no additional parameter clarification beyond repeating the time scope ('days ahead'). With 100% schema coverage, the baseline of 3 is appropriate.

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 precisely identifies the tool's domain: 'Sea state at a coastal or offshore point' and enumerates the specific data (wave height, period, direction, sea temperature). This clearly distinguishes it from sibling weather tools like weather_forecast, weather_air, and weather_history, which cover general forecast, air quality, or historical data.

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 implies use for marine/coastal conditions by specifying 'coastal or offshore point', but it does not explicitly state when to prefer this tool over alternatives or mention any exclusions. Usage context is embedded in the description but not formalized as guidance.

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