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

Annotations already declare readOnly, idempotent, non-destructive, non-open-world behavior, so the safety profile is covered. The description adds genuinely useful non-annotation detail: it returns Medicare's ownership classification, city, main phone, and an interpretation for financial assistance, plus the rule that nonprofit hospitals must have a financial assistance policy. No auth/rate-limit/error behavior is mentioned, but with annotations present the bar is lower.

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 key framing ('Whether a hospital is nonprofit, for financial assistance') is front-loaded and the example queries follow immediately. The final sentence about nonprofit financial assistance policies is slightly redundant with the earlier 'what that means for financial assistance' clause, but it still earns its place as domain context.

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 carries the return-value burden and does so by enumerating ownership type, city, phone, and the financial-assistance interpretation. Combined with the example queries and the 100%-covered input schema, an agent has everything needed to call and interpret this 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 each parameter (name, city, state) is documented in the schema itself, including the note that state is recommended because names collide. The description adds no parameter-level guidance 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?

The description names a specific resource (hospital ownership status) and the practical question it answers, with concrete examples like 'is St. Luke's in Boise a nonprofit?'. The purpose is unmistakable, though it never explicitly contrasts itself with the billing-oriented siblings (check_price, check_whole_bill, draft_bill_letter).

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?

Two natural-language example questions establish exactly when to reach for this tool, which is strong contextual guidance. It stops short of stating exclusions or naming an alternative when the tool isn't appropriate.

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