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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false, and destructiveHint=false, so the safety profile is covered. The description adds genuine value by disclosing the advisory nature of the output (plain-language explanation with NEC citations), though it says nothing about limits, edge cases, or unsupported configurations.

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?

Three sentences with zero padding: capability, trigger condition, and return contents in that order. Nothing repeats the title or wastes the agent's attention.

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 no output schema, the description correctly carries the return contract (wire gauge, breaker amps, EGC size, explanation with citations), and the four input parameters are fully covered by the schema. An agent has everything needed to call and interpret this tool.

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 every parameter (charger_amps, run_length_ft, wire_material, ambient_temp_c) is already documented with ranges, enum values, and defaults. The description adds no parameter-level meaning beyond that, so the baseline 3 is appropriate.

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 names a precise verb and resource ('Recommend breaker size, wire gauge, conduit, and ground wire') and scopes it to 'a home EV charger circuit', which cleanly separates it from check_voltage_drop and check_panel_capacity without opening their schemas.

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 gives an explicit trigger ('Use when a user asks what wire size, breaker, or circuit their charger needs'), which is strong when-to-use guidance. It stops short of naming when-not-to-use or pointing at the sibling tools for adjacent questions (panel capacity, voltage drop).

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