rb209_rainfall_average

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

With no annotations, the description carries the burden of behavior disclosure and states the operation's output as average rainfall for the year. It does not mention return format, units, data source, or error behavior, but for a simple read-only lookup the core behavior is reasonably clear.

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 a single front-loaded sentence with no redundant words. It states the resource and its output efficiently, and every word contributes to the meaning.

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 and the single parameter is fully schema-documented, but there is no output schema and the description omits units and return format. It also does not point to seasonal siblings, so the annual-versus-seasonal distinction is only implied, not explicit.

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 already documents the postcode parameter with its first-half format at 100% coverage, so the description does not need to repeat it. The description only adds 'of the field' as contextual framing, which does not meaningfully expand parameter knowledge beyond 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 description names the endpoint and defines its output as 'average rainfall of the field across the whole year,' clearly conveying an annual rainfall lookup. The 'whole year' qualifier distinguishes it from the summer/winter rainfall siblings, though it lacks an explicit verb like 'retrieves.'

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 annual scope implies when this tool should be used, but it never explicitly mentions seasonal alternatives such as rb209_rainfall_summer_rainfall_average or rb209_rainfall_winter_rainfall_average. No exclusion conditions are stated, so an agent must infer the selection criteria.

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