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

Annotations already state readOnly, openWorld, idempotent, and non-destructive. The description adds substantial behavioral context beyond that: return format (timestamp, numeric value, unit, quality flag), the meaning of quality flags (G=approved, Y=provisional), no API key required, open-data licensing, time-series depth, and station/parameter availability limitations.

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 front-loaded with the core purpose and every subsequent sentence adds useful context: station coverage, parameter variability, return format, common IDs, and licensing. Despite its length, it avoids filler and each detail supports correct tool invocation.

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?

For a tool with one required parameter and well-documented optional ones, the description covers all practical invocation needs: how to identify stations, which parameters exist, what the response contains, how far back data goes, and whether authentication is needed. The combination of schema and description leaves no significant gap.

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 100%, so the schema already documents all three parameters thoroughly, including defaults, enums, and examples. The description adds some helpful reinforcement through common station IDs and parameter IDs, but does not provide meaning beyond what the schema already conveys, so the baseline of 3 applies.

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 opens with a specific verb and resource: "Get weather observations from a specific SMHI monitoring station in Sweden." It distinguishes itself from related SMHI tools by emphasizing observations from a station rather than forecasts, warnings, or fire risk, making the tool easy to identify and select.

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 gives clear context for when to use the tool: when observed current readings or time-series history from a Swedish station are needed. It does not explicitly contrast with sibling tools such as smhi.weather.forecast or smhi.weather.warnings, but the emphasis on observations and monitoring stations makes the intended usage evident.

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