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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety profile is covered. The description adds genuinely useful context beyond that: the discount-rate band it applies (8%–18%), that 'typical range' is used as a judgment criterion, and that offering a lump sum changes the nature of the computation. It does not disclose mortality assumptions behind lifeContingent or any jurisdictional limits.

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 sentences, front-loaded with the core computation and trailing the use case. Slightly dense with the stacked output list, but every clause carries information and nothing is redundant filler.

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 does the work of describing returns (present value, effective discount rate, cents on the dollar, typical-range verdict), which is the critical gap for this tool. Remaining omissions are secondary: how lifeContingent is actuarially handled and whether results are state/jurisdiction dependent.

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% across 9 parameters, so the schema already carries the parameter meanings. The description adds only one semantic detail beyond the schema: that supplying 'offer' turns the tool into an implied-rate/'fairness' judgement rather than a plain valuation. Baseline 3 is appropriate.

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 ('present value ... and effective discount rate') against a specific resource ('structured settlement, annuity or lottery payment stream'), and enumerates the concrete outputs an agent can expect. The sibling tools (discount_rate_index, list_states, state_transfer_rules) occupy clearly different domains, so no ambiguity arises.

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?

Explicitly states the triggering situations: 'when someone asks what their payments are worth, or whether an offer is fair.' That is clear usage context, but it names no alternatives or exclusion conditions (e.g., what to do for non-US or non-stream assets).

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