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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the description's main added value is the pricing model — free within the daily allowance, then $0.001 USDC per call via x402 — which is genuinely important for an agent to know before calling. It omits any note on data freshness or update cadence, which keeps it short of a 5.

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 short sentences, zero waste, with the resource and time horizon front-loaded and the billing caveat second. 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?

For a zero-parameter read tool with an output schema that already documents the return shape, the description covers purpose, horizon, and cost adequately. The remaining gap is the lack of differentiation from the other gb-electricity forecast tools, which matters given how many similar siblings exist.

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?

The tool takes zero parameters, so the baseline is 4. The description correctly adds no parameter detail and instead specifies the forecast horizon baked into the resource, which is the only input-like information relevant here.

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?

States a specific resource and verb ('generating plant surplus forecast') plus a distinct horizon ('days 2–14'), which separates it from the daily/history sibling tools. It does not, however, differentiate itself from the adjacent 'margin-forecast' or 'capacity-forecast' tools, which an agent could easily confuse for the same thing.

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 says nothing about when to reach for this tool versus margin-forecast, capacity-forecast, or indicated-forecast. The only selection hint is the implicit day-2–14 horizon; there are no exclusions or alternatives named.

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