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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered by structured data. For a pure deterministic calculator the remaining behavioral question is rounding and output precision, which the description does not address; the URL adds no runtime context an agent needs to invoke correctly.

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?

One tight sentence that front-loads the computed outputs, followed by an optional reference link. The phrasing is slightly elliptical ('Selling price, profit and margin from...') but nothing is padded.

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 need not be explained, and the tool is a stateless deterministic calculation with one required parameter. The only material gap is not stating precedence when both price and markup_pct are supplied.

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 three parameters are already fully documented and the baseline applies. The description restates the same cost/price/markup_pct pairing without adding format details, ranges, or precedence rules (e.g. which wins if both are given).

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 names the exact quantities computed (selling price, profit, margin, markup) and the two input combinations that drive them, which is concrete enough to distinguish it from siblings like calculate_arr or calculate_churn. It is a sentence fragment with no verb, so it reads slightly as a label list, but the resource is unambiguous.

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 two operating modes ('cost and a markup percent' vs 'cost and a selling price') tell an agent which input combination to supply, but that same guidance is already in the schema ('give this or markup_pct'). There is no statement of when to prefer this tool over a sibling or what happens if both price and markup_pct are provided.

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