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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds non-obvious behavior: a per-call cost of $0.004 USDC via x402 (a real invocation constraint the annotations omit) and that single-state results carry 13 months of history rather than a single snapshot.

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?

One dense sentence front-loads the resource and both modes, with the cost placed last. Slightly clause-heavy, but no filler and nothing redundant with the 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?

For a one-parameter, no-output-schema tool, the description covers the metric set returned, the history depth, the ranking scope, and the payment requirement — everything an agent needs to call it and interpret the result.

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 the single 'state' parameter already documents accepted formats (name or 2-letter code) and the omit-for-ranking behavior, so the description adds no parameter syntax beyond it. Baseline 3 applies when the schema does the heavy lifting.

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+resource (US unemployment by state) and spells out both output modes: a single state's rate/labor force/employed/unemployed, or all 50 states plus DC ranked lowest to highest. It does not explicitly distinguish itself from the sibling 'labor' tool, but the state-level scope is unambiguous from the name and text.

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?

Gives clear mode-selection guidance: pass a state for one state's detail, omit it for the national ranking. It does not name alternatives such as 'labor' (national) or 'wages' for broader labor data, so the agent must infer when to prefer a sibling, but the within-tool conditions are explicit.

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