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

Annotations already establish readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuinely non-obvious behavior: that the EGC is upsized under 250.122(B) when voltage drop increases conductor size, which an agent could not infer from the annotations or schema alone.

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 leading with the deliverable, then the rule set. Dense with code jargon but no filler; every clause corresponds to an actual computation step.

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?

An output schema exists, so return values need no explanation, and all 7 required params are schema-documented. The remaining gap is sibling routing among ten electrical calculators, which the description does not address.

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% with enums on temp/phase/volts/material, so the schema carries parameter meaning. The description references termination temperature and voltage-drop limit conceptually, mapping loosely to `temp` and `limit`, but adds no syntax or format detail 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?

States a specific verb+resource: computes 'minimum conductor size for a circuit', and enumerates the governing rules (310.16 ampacity, 240.4(D), voltage drop, 250.122 EGC). This implicitly separates it from the narrower siblings nec_ampacity and voltage_drop, though it never names them.

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?

There is no when-to-use guidance: nothing tells the agent to pick wire_size over voltage_drop or nec_ampacity, which cover sub-parts of the same computation. The scope is inferable from the rule list but never stated as a selection condition.

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