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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds valuable behavioral context beyond these: 'No auth — US NRC public domain data', 'Returns up to 1000 rows per call', and the 17K–35K row file size detail, which helps agents plan pagination.

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?

The description is three sentences with a front-loaded purpose, followed by data range, record structure, use cases, row limits, and auth. Every sentence serves a purpose with no wasted words.

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?

Covers data availability (1999–current year), optional filtering, record composition, row limits, auth status, and intended analytical applications. The output schema handles return-format specifics, so nothing an agent needs is missing.

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%; the schema already documents each parameter (unit, year, limit) with defaults and ranges. The description only restates the unit filter option ('Optionally filter by reactor unit name') without adding new meaning or syntax. 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 states a specific verb and resource: 'Retrieve full-year historical power status data for US nuclear reactors from NRC annual archives.' This clearly distinguishes the tool from siblings like nrc.reactor.current_status by emphasizing 'full-year' and 'annual archives'.

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 lists concrete use cases ('capacity factor analysis, long-term outage pattern research, nuclear energy generation modeling, and historical grid impact studies') that imply when to use it. It does not explicitly contrast with nrc.reactor.current_status or nrc.reactor.history, but the annual-scope language provides clear context without exclusions.

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