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

Annotations cover read-only and idempotent behavior, so the description adds useful domain context: that the tool doesn't fetch prices or compare named dealers, that it only calculates from user input, and that results should include a link for the user to adjust assumptions. However, it doesn't detail output format or limitations like rounding behavior, and the 4 reflects solid but not exhaustive transparency.

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 quite long and information-dense, with multiple sentences that mix usage guidance, warnings, mode explanations, and disclaimers. While front-loaded with the main purpose, it could be more structured; some sentences repeat the same idea (e.g., overmileage cost) and the length reduces clarity for an agent.

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?

Given the complexity (12 parameters, Swedish market nuances), the description covers key assumptions, modes, and limitations well. It also notes that an output schema exists (by implication of returning a link and breakdown), so it doesn't need to explain return values. It's nearly complete but could briefly mention output shape or error conditions.

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 baseline is 3. The description adds some contextual meaning by explaining the two modes ("erbjudande" vs "avtal") and typical values (36 months, 1000 mil/year, 10–20 kr/mil), which enriches parameter understanding, but it doesn't introduce syntax or formats beyond what the schema already provides.

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 purpose in Swedish: it's a calculator for evaluating whether a private leasing offer is worth it, covering real cost, excess mileage, effective interest rate, and lease-vs-loan comparisons. It clearly distinguishes itself from siblings like forhandla_bolaneranta and hyra_eller_kopa_bostad by focusing on car leasing costs, not mortgages or housing.

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 when to call it (when someone has a private leasing offer and asks if it's worth it, what it costs, etc.) and explains the two modes briefly. It doesn't explicitly say when NOT to use it versus siblings, but the domain is narrow enough that alternatives are implicitly excluded.

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