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

Annotations declare readOnlyHint and openWorldHint, so the safety profile is already covered and the lower bar applies. The description adds genuinely useful behavioral context by disclosing the returned measurements (5-minute snapshot, 24h average, cleanest/dirtiest windows), which is not restated anywhere else since there is no output schema.

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?

A single sentence that front-loads the resource and then packs the returned metrics without any filler or redundancy. Every clause carries information an agent needs.

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?

With no output schema and only one optional parameter, the description correctly compensates by enumerating the return contents, making the tool callable without opening anything else. Only the relationship to the price-focused sibling remains unstated.

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 coverage is 100% and the single enum parameter is already documented, so the baseline would be 3. The description goes further by mapping the opaque enum tokens to meaning (DK1 = West, DK2 = East), which the schema's terse 'Price area.' note does not convey.

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 resource (CO2 intensity per kWh in Denmark, split by DK1/DK2) and precisely enumerates what the tool returns: the latest 5-minute value, a 24-hour average, and cleanest/dirtiest times. It does not explicitly contrast itself with the sibling dk_electricity_prices, so an agent must infer the distinction, but the substance is unambiguous.

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?

Usage is only implied by the resource description; there is no explicit statement of when to prefer this over dk_electricity_prices or what conditions make it relevant. The DK1/DK2 split hints at the geographic selection, but no when-to-use or when-not-to-use guidance is given.

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