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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful context beyond the annotations by enumerating the three returned values, which matters because there is no output schema. It stops short of noting rounding/precision behavior or constraints on the inputs.

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 with the verb first and zero filler. Every clause earns its place by naming the inputs and the three outputs.

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 a two-parameter, read-only calculator with no output schema, the description is nearly complete because it explicitly names the return values (selling price, profit, margin). The only gap is the lack of any statement about precision or how it relates to calculate_profit_margin, which is minor at this complexity.

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 both parameters (cost, markupPercent) are already documented with their meaning and bounds, establishing the baseline of 3. The description restates the two inputs but adds no units, format, or edge-case semantics beyond what the schema provides.

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 (calculate) plus resource and full input/output contract: selling price, profit, and equivalent profit margin from a cost and a markup percentage. This cleanly separates it from the sibling calculate_profit_margin, which works the opposite direction, without the agent needing to open either schema.

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 makes the applicable situation implicit (you have a cost and a markup and want the resulting price/profit/margin), which is enough for a pure calculator. However, it never names the alternative calculate_profit_margin or states when to prefer one over the other, so the routing guidance is left to inference.

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