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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds real domain context beyond them: the governing standard (NF C 15-100), the residential scope, and the fact that a required section is the return value. It does not cover edge cases like minimum section rules or multi-phase wiring.

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?

Front-loaded with the operation and standard, then inputs and return value, ending with a pointer to a sibling listing tool. The 'Inputs: ...' clause is terse but earns its place; nothing is padded.

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?

Output schema and annotations mean the safety and return-shape burden is off the description's shoulders, and it correctly supplies the standard and domain. The unresolved kW-vs-W discrepancy and the silence about calculate_cable_section_electrical leave two gaps an agent must guess through.

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%, so baseline would be 3, but the description actively misstates the input model: it says 'power kW' while the schema parameter is power_w in watts, and omits that voltage and max_drop_pct have defaults. A unit mismatch of 1000x is worse than silence and can cause a wrong invocation.

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 and resource ('Compute electrical cable cross-section (mm²)') and anchors it to a named standard (NF C 15-100), which is genuinely distinguishing. However, it never acknowledges the near-identical sibling calculate_cable_section_electrical, so an agent cannot tell which of the two to pick from the description alone.

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?

'Use for residential wiring' implies the applicable domain but gives no when-not conditions or explicit alternative routing. The only routing hint ('See list_bundles for related construction calculators') points to a discovery tool rather than to a competing calculator, so conflict resolution is left implicit.

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