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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds nothing behavioral beyond that — no mention of result ordering, tie-breaking, timezone/date boundary for "i dag/i morgen", or what happens when the requested hours span a day change. For a pure read tool this is an acceptable but thin contribution.

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, front-loaded with the action and scope, then immediately the practical use case. No filler, no repetition of title or schema content, and the quoted user phrasing is compact and aids intent matching.

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 zero-required-parameter, read-only query with fully documented schema, the description is sufficient to call the tool correctly, and the use-case framing substitutes well for an output schema. Minor gaps remain around returned ordering and the day-boundary semantics of "today/tomorrow" in Danish local time.

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%, with both enums (area, mode) richly documented in the schema itself, so the baseline of 3 applies. The description only implies the `hours` and price-zone concepts already spelled out in the schema, adding no semantics such as whether `hours` must be contiguous or how ties are resolved.

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?

"Find the N cheapest hours of the day for a price zone" gives a specific verb (find/rank) and resource (cheapest hours), and the concrete use cases (EV charging, heat pump, dishwasher) make the intent unambiguous. It does not name any sibling such as get_current_price or get_price_forecast to draw the boundary explicitly, so it stops short of a 5.

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 states clearly when to reach for this tool: scheduling deferrable loads, and it even anchors the intent to a natural-language Danish query ("hvornår er strøm billigst i dag/i morgen"). There are no explicit exclusions or named alternatives that would tell an agent when to pick get_today_prices or get_current_price instead.

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