engineering.fluid_reynolds

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

Annotations already establish readOnly/idempotent/closed-world, so safety is covered. The description adds real behavioral substance beyond that: inputs must be numeric strings, all must be strictly positive, and the computation runs at 50 significant digits with no rounding.

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 compact paragraph with the formula front-loaded, followed by inputs, constraints, caveat, and precision note. No sentence is redundant and nothing is buried.

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?

With an output schema present, return values need no explanation; the description still covers inputs, unit conventions, validity limits, classification thresholds, and numeric precision. An agent has everything needed to call it correctly and interpret the result.

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 0% and the schema has only bare titles, so the description must compensate — and it largely does, assigning units (kg/m³, m/s, m, Pa·s) to each quantity and requiring numeric strings above zero. The mapping from unit to named parameter is implicit via the formula and names rather than spelled out parameter-by-parameter.

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 the exact formula (Re = ρvL/μ), the computation, and the three-way classification with numeric thresholds. An agent immediately knows this is a Reynolds-number calculator, distinct from siblings like darcy_weisbach or moody_friction_factor.

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?

It explicitly bounds applicability: the 2300/4000 thresholds are for pipe flow and do not hold for flat plates or other geometries, which tells the agent when results are invalid. It does not point to any alternative tool, but no sibling performs this same computation, so the gap is minor.

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