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

Annotations already establish readOnly/non-destructive/closed-world, so the bar is lower, and the description still adds real value: data provenance (hospital price transparency and Medicare data), the vintage disclosure, and the explicit caveat that these are estimates, not quotes. It does not cover latency, coverage gaps by state, or error behavior.

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?

Three sentences, front-loaded with the primary return shape, then the conditional patient-share behavior, then the input requirements. Slight redundancy in restating the required/optional split already present in the schema, 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 no output schema, the description carries the return-value burden and does so: it enumerates the range fields, billing components, vintage, and the conditional patient share. Combined with the estimate-not-quote disclaimer, an agent has enough to call it and set expectations correctly.

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 the baseline is 3, but the description adds meaning beyond the schema: it states that deductible/coinsurance/OOP inputs are user-supplied optional figures that only conditionally trigger a patient-share result, and that ZIP is used 'only to refine the local estimate'. That clarifies the conditional role of the optional parameters better than the field descriptions alone.

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 verb (returns) plus concrete outputs: an allowed-amount range (low/median/high) for ONE procedure in ONE US state, billing components, and data vintage. Scope ('one medical procedure in one US state') helps distinguish it from broader siblings like full_estimate, but no sibling is named explicitly.

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 clarifies the required-vs-optional split and that plan figures 'are used only for this one calculation', which is useful conditional guidance. However it never states when to prefer this over full_estimate, demo_estimate, or calculate_liability, nor when to route procedure-name matching through resolve_procedure (that hint lives only in the schema).

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