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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds meaningful behavioral detail beyond annotations: rounding to the currency and rounding each tax component separately, plus QuoteBill parity. There is no contradiction with the annotations.

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?

A single front-loaded sentence states the core action first ('Adds up line items, applies discounts, and applies the tax'), then adds a precise qualifier about rounding. Every word earns its place with no 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 an output schema present and full parameter coverage in the schema, the description only needs to convey the calculation behavior, which it does thoroughly, including the rounding nuance. No critical behavioral aspect for invoking the tool 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 coverage is 100%, so all four parameters are already documented in detail. The description mentions applying discounts and tax for a country, which loosely maps to lineItems and country, but it adds no syntax, format, or parameter-specific meaning beyond the schema. 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?

The description states a specific verb and resource: it 'Adds up line items, applies discounts, and applies the tax for a country.' It also distinguishes itself from siblings by referencing QuoteBill's exact arithmetic, making clear this is a calculation tool rather than a retrieval or document-building tool.

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?

The description gives clear context by noting it uses 'the same arithmetic QuoteBill uses,' implying this is the canonical totals calculator. It does not explicitly name alternatives or when to avoid it, but among siblings only get_tax_rule is vaguely related, so the usage context is mostly clear.

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