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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so safety and determinism are covered by structured data. The description adds the genuine behavioral fact that the tool serves two distinct calculation regimes (Ohm's law pair-solving and AC watts-to-amps), but does not state that inputs are pure computation with no side effects or how the two regimes are selected. Modest added context over 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?

Three compact sentences: primary function first, secondary AC capability second, reference link last. Nothing is padded or repeated. The trailing marketing URL is the only low-value element, so it stops short of a 5.

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?

Eleven optional parameters, three enums (mode, phase, solve), duplicated quantity parameters and no output schema make this a genuinely complex call, yet the description never explains the mode switch, the phase/pf inputs, or the 'solve' selector. An agent must reverse-engineer the parameter subsets from the schema alone, which is a meaningful completeness gap.

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 the per-parameter descriptions (e.g. 'Current (I) (A)', 'Power factor...0.8-0.95 for motors') carry the baseline burden and the score floors at 3. The description adds the real semantic rule that any two of V/I/R/P determine the rest, but it never resolves the schema's duplication problem: 'i' vs 'amps', 'p' vs 'watts', and 'v' vs 'volts' are never mapped to the ohm/power modes, and 'ohms' in the description does not match the 'r' parameter name.

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 computation clearly: 'Enter any two of volts, amps, ohms and watts to get the other two,' plus a second capability (watts-to-amps for DC/1-phase/3-phase AC). That is far more specific than 'Ohm's law calculator' alone. It does not differentiate itself from nearby siblings such as scientific_calculator or electricity_cost_calculator, which keeps it from a 5.

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?

'Enter any two of volts, amps, ohms and watts' implicitly tells the agent what inputs to supply for the primary calculation. However, it gives no guidance on when to choose mode='ohm' versus mode='power', when phase/pf matter, or what to do if the caller has only one known quantity. Usage is implied rather than stated.

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