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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, fully covering the safety profile for a stateless calculator. The description adds no behavioral detail beyond that (no note on determinism or return format), so it neither helps nor harms.

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 that delivers the tool's full scope with no filler. Every clause earns its place by naming one of the three supported computations.

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 simple three-parameter calculator with no output schema, the description covers all three modes and the required values. The only omission is what the result looks like (a number, a percentage), which is minor given the simplicity.

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%, but the schema only labels mode as 'Calculation mode (default of)' without decoding the enum values. The description maps each mode to plain English ('X% of Y', 'X is what % of Y', '% change from X to Y'), which is genuine added value beyond the schema.

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 (Solve) and resource (percentage problems) and then enumerates the three exact computations the tool performs. This implicitly separates it from siblings like discount_percent_off or win_loss_percentage, though no sibling is named explicitly.

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?

Listing the three problem types implies when to reach for this tool, but there is no explicit guidance on when to prefer it over siblings such as discount_percent_off or tip_bill_split, and no exclusions. Usage is inferable rather than stated.

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