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

Beyond the readOnly/idempotent annotations, it discloses the data is final/bounded annual national data, the self-hosted release source, the 2019–2025 coverage window, and the non-forecast/non-state-county scope. It also enumerates output components (values, units, crop class, source file, pagination, evidence hash, attribution), which is valuable context for callers.

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 compact and front-loaded: it states the core behavior first, then gives example queries, scope, and exclusions. The inclusion list is mildly listy and the 'self-hosted 2020–2026 annual-summary releases' phrase is dense, but every sentence 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?

With no output schema, the description supplies a useful summary of return contents, year coverage, and non-scope exclusions. It does not spell out pagination behavior or response_format semantics, but those are covered by schema parameter descriptions, so the overall context is sufficient.

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%, so the schema already documents all 8 parameters, enums, and defaults. The description's examples reinforce the crop/metric mapping but do not add materially new parameter-level meaning beyond what the input schema provides.

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 opens with a specific verb and resource ('Return bounded final annual USDA NASS national history for one major-crop metric') and scopes it with examples and exclusions. It is immediately distinguishable from trend, compare, and search siblings by emphasizing a single-metric national history and explicitly saying it is not a forecast or state/county result.

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?

It gives explicit use-this-for examples and a clear when-not ('not a forecast or state/county result'). However, it does not name the sibling NASS tools (e.g. usda_nass_crop_trend or usda_nass_crop_evidence_pack) or state which conditions should route an agent to them.

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