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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description adds useful behavior beyond that: it discloses that a per-phase load total plus an imbalance figure is produced. It does not say how circuits are assigned to phases or whether balancing is optimized, so it only partially extends the annotations.

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 dense sentence that front-loads the action and the panel types. Nothing is wasted, though it could have spent one more clause on when to prefer it over load_calculator.

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 a 100% covered schema, an output schema, and safe-read annotations, the description needs only to frame the purpose and it does that adequately. The gap is the absence of any guidance on phase assignment strategy or how the tool relates to the other load/wire calculators.

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%, including enum meanings for system and spaces and the 'description, breaker A, poles, VA' line format for circuits, so the schema carries the parameter burden. The description echoes the two voltage systems but adds no syntax or format detail beyond the schema, making the baseline 3 correct.

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 action and object: it lays circuits out on a panel and totals load per phase with imbalance, naming the supported systems (120/240 V single-phase, 208Y/120 V three-phase). This is clearly distinguishable from pure calculation siblings like ohms_law or voltage_drop, though it does not explicitly name a sibling it replaces.

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 description gives no when-to-use guidance, no prerequisites, and no routing hints against load_calculator or the other electrical siblings. Usage is only inferable from the purpose statement itself, which is below the 'implied usage' threshold of an explicit context cue.

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