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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered. The description earns credit for genuine domain caveats beyond the annotations: source-scoped results, collection timestamps not backdating publication dates, and the warning not to sum overlapping sources or cumulative benchmarks. It omits, however, any hint of result volume or pagination behavior, which matters for a tool with a default limit of 5000 and a max offset of 500000.

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?

Three sentences, front-loaded with the data content, with no filler. But the phrasing is compressed to the point of ambiguity ('Collection timestamps never backdate publication dates') and the final clause crams two separate warnings into one sentence without specifying which parameters they map to.

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 14 undocumented parameters, no output schema, and no annotation detail on paging or cardinality, the description should do much more. It leaves the meaning of the `historical` toggle, the `kind` enum values, and the pagination contract unexplained, so an agent cannot confidently construct a call from this definition alone.

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 0% across 14 parameters, so the description carries the full burden. It only illuminates region, fuel, status and implicitly sourceId; it says nothing about the `historical` boolean, the `kind` enum (queue/load/capacity/utility), `symbol`, `country`, `loadClass`, `search`, or the limit/offset paging contract. The crucial distinction it hints at ('current collection history or historical benchmark series separately') is never tied to the `historical` flag an agent must actually set.

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 the resource content (observed MW and project counts by region, fuel and status) and the source-scoping, so an agent learns what data comes back. But it never states the core verb or temporal nature directly – the fact that this is a time-series/history retrieval over a range is inferred from the name and title rather than the text. It also does not distinguish itself from power.board, power.summary or power.coverage, all of which plausibly return similar MW aggregates.

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?

'never sum overlapping sources or cumulative historical benchmarks' is an aggregation caution, not routing guidance. There is no statement of when to call power.history versus power.board/power.summary/power.project, no prerequisites, and no indication of whether a time range is required despite the presence of from/to parameters.

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