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

Annotations already declare readOnlyHint=true, openWorldHint=false and idempotentHint=true, so the safety profile is covered. The description adds genuine value beyond them by disclosing the return shape (a list of records) and the cursor-based pagination contract, which no structured field provides 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?

Two compact sentences that front-load the resource and then cover pagination and return fields without padding. The only minor waste is that the first sentence duplicates the title verbatim rather than adding information.

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 seven-parameter read-only list tool with no output schema, the description usefully fills the output gap by enumerating the returned fields and explaining cursor pagination, while annotations cover the safety profile. It falls short only on undefined terms ('forecast') and the missing relationship to the electricity_balance sibling.

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 parameter meanings (year equals, year_gte/lte, series_in, limit, cursor) are already fully documented in the schema. The description's field list (year, series, twh) describes output columns rather than adding parameter semantics, so the baseline 3 is appropriate.

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 (electricity production per source) and notes it includes forecast values, so an agent knows what the tool surfaces. However, the opening sentence is a verbatim restatement of the title and it never distinguishes this from the very similar sibling electricity_balance, leaving selection ambiguous.

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 explains pagination mechanics ('pass next_cursor to get the next page') but gives no guidance on when to use this tool versus alternatives. With electricity_balance as a near-identical sibling and no exclusions or selection criteria stated, routing remains guesswork.

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