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

Annotations already cover readOnly/idempotent/non-destructive, so the bar is lower; the description adds real value by disclosing the 2019–2025 coverage bound, the self-hosted 2020–2026 release provenance, national-only granularity, and the returned artifacts (evidence hash, attribution, pagination). It stops short of describing pagination semantics or the failure mode when a year falls outside coverage.

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 core action and scope, then examples, then the exclusion clause. The enumerated return fields add length but each item earns its place given there is no output schema.

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 no output schema, the description compensates by naming the returned fields, and it declares the year-coverage ceiling that the schema merely echoes. Missing only error/edge behavior, which is minor for a bounded read-only history tool.

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% and two enums are documented, so the schema already does the heavy lifting for crop, metric, crop_class, and year bounds. The description reinforces year coverage and crop-class relevance but adds no syntax or defaulting detail beyond the schema — 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?

States a specific verb and resource: 'Return bounded final annual USDA NASS national history for one major-crop metric', and pins the scope to national, final (non-forecast) annual summaries. The 'not a forecast or state/county result' clause cleanly separates it from siblings like usda_nass_crop_trend or usda_nass_search_crop_series.

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?

Provides three concrete example queries and gives explicit exclusions (not a forecast, not state/county). It does not name a specific sibling to use instead for forecasts or sub-national data, so the routing is implied rather than stated.

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