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

Annotations already declare readOnlyHint and openWorldHint, and the description adds genuinely useful non-schema context: the $0.002 USDC x402 payment model (Base, Solana, Arc) with failed calls not charged, plus the LCOE exclusion. It does not disclose update cadence, pagination, or rate limits, so it is solid but not rich.

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?

Purpose and units are front-loaded, followed by the LCOE exclusion and pricing in two additional compact clauses. The long parenthetical technology list is informative but slightly heavy for a single sentence.

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 an output schema present, return values need no explanation, and the description covers scope (single country), units, technology coverage, and explicit exclusions. Data freshness/update lag and whether years are annual are the only notable gaps.

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%, so the baseline is 3. The description adds meaning by enumerating the technology categories (solar PV, onshore/offshore wind, hydropower, bioenergy, geothermal) and framing years as 'recent years', giving the agent a better mental model of the filters than the schema alone.

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 verb+resource (IRENA renewable energy statistics: installed capacity in MW and generation in GWh) scoped to one country, and enumerates the technology breakdown. It also explicitly excludes LCOE, which separates it from cost-benchmark siblings like energy_nrel_atb_cost_benchmarks or energy_iea_energy_statistics_api.

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?

'for one country' and 'from IRENA's public IRENASTAT database' give a clear usage context, and the LCOE exclusion implicitly routes cost queries elsewhere. However, no sibling is named and there is no explicit when-to-use/when-not statement against comparable statistics tools.

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