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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint. The description adds valuable context: it enumerates the data structure (event type, level, areas, time windows), explains the severity scale, notes the official source and open licensing, and clarifies that the language parameter does not affect API behavior. This goes beyond the annotations without contradicting them.

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 dense but effective, front-loading the core purpose in the first sentence and then providing necessary enumerations (levels, event types) and contextual details (authority, licensing). Each sentence contributes useful information, with no filler, though it is somewhat long.

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?

With an output schema present, the description does not need to explain return format, but it provides a rich overview of the content (event types, levels, affected areas, time windows) and clarifies the origin and reliability. It covers the essential information an agent needs to decide when and how to call the tool, leaving no obvious gaps.

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 coverage is 100% and the schema description already explains the language parameter ('preference not sent to API', English/Swedish area names). The tool description does not add meaning beyond that; it merely restates that warnings include English. Since schema carries the semantic load, a score 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 states a specific verb ('Get all currently active official weather warnings') and a clear resource (SMHI for Sweden). It enumerates return fields and both warning levels and event types, making its purpose unambiguous and distinguishing it from sibling tools like smhi.weather.forecast or smhi.weather.fire_risk.

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 clearly indicates it returns active official warnings, implying it is for real-time alerting rather than forecasts or observations. However, it does not explicitly state when to use it versus alternatives (e.g., 'for forecasts use smhi.weather.forecast'), so guidance is implied rather than explicit.

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