SMHI: hvilke værdata måles?

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

With no annotations, the description carries the behavioral burden, and it adds meaningful context: results are observations of past weather, SMHI has no forecasts here, and data is from a CC BY 4.0 licensed source. It does not detail response structure or pagination, but for a simple zero-parameter metadata list that gap is minor.

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 core purpose is front-loaded in the first sentence, and the 'START HER' instruction is highlighted early. The source/license line is slightly extra for invocation purposes but not excessive, keeping the description compact and readable.

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 parameter-count tool with no input schema, no output schema, and no annotations, the description covers the essentials: what is returned, why to use it first, and the observation-not-forecast caveat. It could mention the exact output shape or whether all parameters are returned at once, but the current level is adequate for correct invocation.

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 tool has zero parameters and the schema coverage is 100%, so the baseline is 4. The description goes slightly beyond by indicating the useful output content (code and unit) and giving examples of parameters, which helps the agent interpret what it will receive.

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 uses a specific verb and object: 'Lister målte parametere ... med kode og enhet', making it unmistakably a parameter-catalog tool. It also distinguishes itself from sibling tools by declaring 'START HER — kodene trengs av de andre verktøyene', placing it as the entry point before smhi_stasjoner and smhi_observasjoner.

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?

It explicitly says to start here because the codes are needed by the other tools, which tells the agent when to invoke it. It also states this is observations, not forecasts, so it should not be used for forecast lookups, though it does not name the alternative forecast tool.

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