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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior. The description adds that the calculation considers both ampacity and voltage drop and returns resistance, power loss, and a fuse recommendation; it still does not describe output format or edge-case behavior, but with annotations covering safety this is solid.

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?

The description uses four compact sentences: purpose, calculation basis, additional returns, and supported conductor range. It is front-loaded and every sentence contributes useful scope without repetition or waste.

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?

For a read-only calculator with full parameter schema coverage and annotations, the description covers purpose, calculation basis, supported conductor range, and several return values. Because there is no output schema, it could be more complete about the exact response shape, such as whether voltage-drop and ampacity values are included, but it is largely sufficient.

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 each parameter already has documentation and the description only needs to add meaning beyond the schema. It mentions ampacity and voltage drop conceptually but provides no additional parameter syntax, defaults, or constraints beyond what the schema already states.

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 a specific verb ('Calculate') and resource ('wire gauge / cable cross-section') for DC circuits, and enumerates the criteria and extra outputs, so the core purpose is unambiguous. It does not explicitly contrast itself with sibling calculators, so it stops short of full sibling differentiation.

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 scopes usage to DC circuits and copper conductors from 0.75 mm² to 240 mm², which implies appropriate context. It does not state when to use a sibling tool or when not to use this one, such as for AC or aluminum conductors, so guidance is only implied.

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