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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds the aggregation semantics (totals and averages per recipient per state), which is useful beyond the annotations. It does not disclose whether the tool returns only the top states by default or what happens when the optional limit is omitted, but the annotations carry the main behavioral burden.

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?

Two concise sentences with the core function stated first and a practical use case added second. Every sentence contributes something: what it returns and why you would use it. It could arguably add a short caveat about interpretation, but there is no waste.

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 simple read-only tool with one optional parameter, full schema coverage, and no output schema, the description is complete enough. It explains the aggregation level, the returned metric type, and a realistic use case. It doesn't need to detail return values because there is no output schema and the description covers the essential output semantics.

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 for the single parameter 'limit' is 100%, so the schema already documents it as 'Max states (default 60)'. The description does not add further parameter-level detail, but with full schema coverage the baseline of 3 is appropriate; nothing important is missing.

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 clearly identifies a specific verb and resource ('Returns payment totals and average per recipient per state') and states the domain ('State-level Open Payments totals'). It distinguishes itself from siblings like open_payments_national_summary and open_payments_by_company by naming the state-level aggregation. It doesn't explicitly name a sibling, but the scope is clear enough.

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 signals the tool is for 'state-level pharma-influence research', which implies a use case context. It does not explicitly state when not to use it or which sibling alternative to choose instead (e.g., open_payments_national_summary for national totals, open_payments_by_company for company-level breakdowns). The context is helpful but not fully explicit.

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