Etsy fees for one order

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

Annotations already declare the safe-read profile (readOnly, idempotent, non-destructive, closed-world), so credit goes to what the description adds: the output payload (itemized breakdown, assumptions, fee table version/date, source URLs), the fee engine's provenance, and non-obvious validation behavior ('invalid or unknown arguments are rejected with a message naming the field, never silently adjusted'). It does not disclose rounding behavior or how discounts interact with fee bases, which keeps it short of 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?

Front-loaded with purpose and usage before mechanics, and every clause carries information (fee rates, unit conventions, validation, output). It is dense to the point of being a run-on, and the shoptrueprofit.com provenance plus the trailing 'link to the matching free calculator' are mildly promotional, but nothing is filler-grade.

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?

For an 8-parameter, fully schema-documented, output-schema-backed tool, the description covers the remaining gaps an agent needs: when to use it, unit conventions, strict-argument-rejection behavior, and the shape of the response. Nothing required to invoke it 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 coverage is 100%, so the baseline is 3, but the description adds a real convention not spelled out in the schema: '*_pct arguments are percents: 8.25 means 8.25%', which prevents a decimal-vs-percent call error. The 'money is in whole cents' statement is ambiguous and arguably sits oddly against schema fields using multipleOf 0.01 (which reads as currency units), so the added value is real but not clean.

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 and resource ('Calculate Etsy seller fees for one order') and immediately distinguishes itself from the sibling etsy_profit by scope ('what Etsy takes from a sale' vs. 'when you also know your costs'). The fee components named (listing, transaction, payment processing, Offsite Ads) further pin down exactly what is computed.

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?

Explicit routing guidance: 'Use when you need what Etsy takes from a sale; use etsy_profit when you also know your costs.' This gives both the trigger condition and the named alternative with the condition that selects it, so an agent can choose between the two fee/profit tools without opening schemas.

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