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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuine context beyond that: the output mirrors the web calculator's grouping, labels and tooltips, and no computation is triggered. It does not mention locale-driven variation in the returned text, which would have earned a 5.

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, zero waste. What the tool returns comes first, the usage condition second, mirroring the order an agent needs them.

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 structure needn't be spelled out, yet the description still characterizes the payload (all fields, web-calculator grouping, label plus tooltip explanation) and defines the invocation context. Nothing needed to call this correctly is missing.

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 the single locale parameter is documented with an enum and default, so the schema carries the semantics. The description says nothing about locale or how it changes the returned explanation text, so there is no value added over the schema — baseline 3.

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?

Specific verb (returns) and resource (every field calculate_osvc_taxes accepts) with explicit scope: grouped like the web calculator with the same labels and tooltip explanations. It names the sibling calculate_osvc_taxes and distinguishes itself by delivering metadata rather than a computation.

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?

States the exact condition for use — explain an option to the user before they've chosen a value — and the exclusion — without running a calculation. That implicitly and correctly routes the agent away from calculate_osvc_taxes when only descriptive text is needed.

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