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

Annotations already declare readOnlyHint=true, non-destructive, closed-world, so safety is covered. The description adds the formula and output unit, which is real context beyond annotations, but says nothing about error handling, precision, or return format (though an output schema exists).

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?

Two short clauses, formula front-loaded with output unit, then the disambiguation. No waste at all.

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 trivial two-param closed-formula calculator with a 100% covered schema, full annotations, and an output schema, the description is adequate. However, it doesn't clarify the relationship to calculator_pressure (the converter) beyond a passing phrase, which is the main ambiguity an agent might hit.

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% — both force (Newtons) and area (m², non-zero) are documented in the schema. The formula in the description reinforces which param is numerator/denominator but adds no format or constraint detail beyond the schema. Baseline 3 applies.

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 the formula P = F / A and the output unit (Pascals), which is a specific verb+resource for a computational tool. It also distinguishes itself from calculator_pressure (unit converter), though it doesn't differentiate from the many other physics siblings (force, work, power).

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 only guidance is a negative disambiguation: 'Distinct from pressure unit converter.' It doesn't say when to use this vs calculator_pressure or calculator_physics_force, but the formula itself implies the use case (compute pressure from force and area).

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