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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description adds valuable context beyond annotations: 'live' rates signaling external variability, 'NOK, inkl. mva' currency/VAT behavior, and the free-Hamar pickup nuance. No contradiction with 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?

Two sentences with zero filler. The first sentence is now the purpose with the currency and domain detail, the second gives routing guidance for the sibling. Every clause earns its place.

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?

Usage routing and semantics are adequate given the strong annotations, but the tool has no output schema and the description never hints at the return shape (rate structure per delivery mode), and the items parameter is unexplained. For a 2-param tool, the gaps are moderate: an agent could call it correctly but wouldn't know what result to expect.

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 only 50% (postcode is described, items is not), so the description must compensate. It confirms the postcode is Norwegian, but 'items' is entirely undocumented in both schema and description — no hint about how sku/quantity affect rates or how the array relates to the checkout. The tool is very vague on building the parameter that drives pricing.

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 names a specific verb plus resource — 'Henter live fraktpriser (NOK, inkl. mva)' — and defines its exact scope: pickup point and home delivery to a Norwegian postal code, plus the Hamar free-pickup special case. It also names the sibling create_checkout and tells the agent to call it first, which distinguishes it from the checkout flow without opening schemas.

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?

'Kall denne før create_checkout når kunden du ikke skal hente selv' explicitly states when to use the tool (before create_checkout for non-pickup customers). It names the relevant sibling but does not give explicit when-not guidance or alternative conditions beyond the Hamar pickup implication.

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