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

Annotations only say read-only and open-world; the description adds the things they cannot: a concrete price ($0.002 USDC per successful call), the payment rail (x402 on Base, Solana or Arc), and the billing rule that failed calls are free. It also discloses the 7-day lookback window in the returned status, which shapes result expectations.

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?

Front-loaded with the resource and its fields, then filters, then price; no filler sentences. The field enumeration is partly redundant with the existing output schema and is the only real bloat, but it stays readable in three sentences.

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?

Cost, payment rail, coverage window, and filterable dimensions together with a full schema and an output schema leave little an agent needs to guess. Missing only edge behavior such as result caps, pagination, or no-match handling.

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 each parameter already carries a description with an example, so the schema does the work. The description's 'filter by state, operator, reactor type or name' restates the same four fields without adding matching semantics (substring vs exact), so baseline 3 applies.

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 precise resource (US NRC operating reactor licences), enumerates the entity's key attributes, and adds the joined daily power-status dataset. An agent can distinguish it instantly from every sibling, none of which touch nuclear regulatory or plant-status data.

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 closing 'Filter by state, operator, reactor type or name' plus the pricing note makes the intended query pattern and cost model clear, so an agent knows how to invoke it and what it costs. It does not explain when to prefer a broader energy source (e.g. gov_energy_gov) instead, so exclusions/alternatives are absent.

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