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

Annotations already mark the tool as read-only and idempotent. The description adds useful behavior beyond that: it lists all returned rent fields, explains that monthly rent is derived as annual rent divided by 12, and discloses that each response includes an attribution field intended for display. This is valuable context not present in the schema or annotations.

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 compact and information-dense: the first sentence states the operation and inputs, the second details all output fields and derivation, and the third covers the attribution requirement. Every sentence earns its place with no filler or repetition.

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?

Since there is no output schema, the description compensates well by explicitly listing rent78, rent91, rent12, their monthly equivalents, and the monthly rent derivation. It also explains the attribution field, making the tool's behavior sufficiently complete for an agent to select, invoke, and interpret results correctly.

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 documents all four parameters with meaningful descriptions, so the baseline is 3. The tool description adds little beyond summarizing that correction points are optional and that area and normhyra are inputs, which does not significantly extend the schema's parameter coverage.

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 ('Räkna om') and clearly identifies the resource and transformation: converting a normhyra in kr/m²/år to an actual annual rent in kronor. It is further differentiated from siblings by naming the exact output fields for three norms and the associated monthly rents.

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 establishes the input context: a norm rent, apartment type, area, and optional correction points are needed to compute actual rent. However, it does not explicitly say when not to use this tool or how it compares to siblings like calculate_normhyra or calculate_rent_roll, so usage 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.