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

Annotations (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false) already make clear this is a safe, side-effect-free computation. The description adds little behavioral context beyond that, though the worked example implicitly reveals the shape of the result (realValue, equivalentNeeded) and the fact that it's a pure calculation with no state change.

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 purpose and followed by a compact numeric example that earns its space by defining the two outputs. No filler or repetition.

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?

An output schema exists, so return values needn't be spelled out, and annotations cover the safety profile; parameters are fully documented in the schema. The description supplies purpose and an illustrative example, leaving only sibling differentiation and language-formatting behavior unaddressed.

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%, so the schema already documents amount, rate (default 3), years (1-80), and the lang enum with formatting implications. The example ties amount/rate/years to outputs but adds no semantics beyond the schema, so the baseline of 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 states a specific dual purpose with a concrete verb and resource: computing real purchasing-power loss to inflation and the nominal amount preserving buying power. The worked example ({amount:100000, rate:3, years:10} → realValue ≈ 74,409, equivalentNeeded ≈ 134,392) makes the output tangible. It doesn't name or contrast against nearby siblings such as compound_interest or cost_of_waiting, so it stops short of 5.

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?

Usage is implied by the example and the purpose framing, but there is no explicit when-to-use or when-not-to-use guidance, and no routing to alternatives like compound_interest or cost_of_waiting, which are adjacent concepts an agent could confuse with this one.

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