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

Goes well beyond the readOnly/openWorld annotations by disclosing the upstream source (USDM public API), the exact charge ($0.002 USDC per successful call), the payment rails (x402 on Base, Solana, Arc), and that failed calls are free — critical for an agent deciding whether to call. No behavior is contradicted.

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 scope, followed by exclusions and pricing; every clause carries information. Slightly dense in a single long sentence, but nothing is wasted.

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; annotations cover safety. The description supplies what those fields cannot — data source, geographic granularity limits, and cost model — so an agent can call it confidently.

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 both parameters are already documented, including the Tuesday/YYYY-MM-DD format and the FIPS example. The description restates '5-digit FIPS' and 'weekly map date' but adds no format or edge-case detail beyond the schema, so the 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 specific resource (US Drought Monitor county statistics) with exact scope: one county by 5-digit FIPS, one weekly map date, returning percent area in no-drought plus D0–D4 categories. It also explicitly bounds itself ('County level only; crop-specific indices are not included'), which separates it from crop-report siblings.

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?

Context is clear: county-level drought percentages for a single FIPS/date, with the default date behavior implied. It excludes crop-specific indices, steering the agent away from misuse, though it never names the sibling tools an agent should pick instead for crop or non-US data.

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