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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered by structured fields. The description adds one genuine behavioral detail beyond them — that the output is the *minimum* required diameter, i.e. a lower-bound sizing result rather than an arbitrary diameter — but says nothing about the standard applied, output units, or edge cases, which is acceptable since 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 sentences, purpose front-loaded, nothing redundant or padded. The second sentence is a cross-reference to list_bundles that is useful in a tool family this large, though it is generic navigation rather than core definition content.

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 full schema coverage, explicit annotations, and an output schema that carries the return shape, the description's only remaining burden is purpose and scope, which it covers cleanly. It falls just short of complete because it offers no disambiguation from the sibling calculate_pipe_flow_rate, the inverse calculation an agent could easily confuse it with.

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 are already documented with units (L/min, m/s) and the DTU-norm default of 1.5 m/s. The description merely restates the two input names ('flow rate and maximum velocity') with no added semantics such as acceptable ranges or unit overrides, so the 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 a specific verb+resource ('Calculate the minimum pipe diameter') and pins down the inputs that produce it (flow rate, maximum velocity), so the agent knows exactly what computation is performed. It does not, however, distinguish itself from the near-neighbor calculate_pipe_flow_rate or other plumbing/hydraulics siblings; the only routing hint points at list_bundles rather than a competing tool.

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?

Usage is only implied: the plumbing context ('plomberie') and the flow-rate/velocity inputs make the domain inferable, and the list_bundles reference is a navigation aid, not a when-to-use rule. There is no statement of when to choose this over calculate_pipe_flow_rate, calculate_cable_section, or the many other sizing calculators, and no prerequisites or exclusions.

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