calc.engineer

watts to amps

watts_to_amps

Converts electrical power in watts to current in amps (and milliamps) for a given voltage, using the DC power formula P = V * I. Also computes the implied load resistance via Ohm's law (R = V / I) assuming a purely resistive load. This is the most common electrical conversion for circuit design, fuse selection, wire sizing, and breaker rating. Use the output amps value to feed into wire_gauge for conductor sizing or voltage_drop for cable loss analysis. Covers DC circuits; for AC with power factor, adjust watts to true power first.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`watts`	Yes	Power in watts (W)
`voltage_v`	Yes	Voltage in volts (V)

Output Schema

TableJSON Schema

Name	Required	Description
`amps`	Yes	Current in amperes (A)
`watts`	Yes	Input power echoed back (W)
`milliamps`	Yes	Current in milliamperes (mA)
`voltage_v`	Yes	Input voltage echoed back (V)
`implied_resistance_ohm`	Yes	Implied load resistance in ohms assuming resistive load (V/I)

TDQS

A4.5/5.0

Behavior5/5

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

With no annotations, the description fully explains the formula P=V*I, the additional computation of resistance via Ohm's law, and the DC-only scope. It transparently covers what the tool does, which is purely computational with no side effects.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, well-organized paragraph of six sentences. It is front-loaded with the core conversion, then expands on resistance, and ends with usage guidance and limitations. No unnecessary words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the low complexity (2 simple number parameters, no nested objects, output schema exists), the description is complete. It explains the output briefly and provides integration points with other tools.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema has 100% coverage with descriptions for each parameter. The description adds extra meaning by explaining the context (DC power formula, resistance calculation, and downstream usage) that is not in the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool converts electrical power (watts) to current (amps and milliamps) given voltage, using the DC power formula. It also mentions computing load resistance. This distinguishes it from sibling tools like ohms_law (which does voltage/current/resistance) and battery-related tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description suggests using the output amps for wire gauge and voltage drop analysis, and mentions that for AC with power factor, one should adjust watts to true power first. It does not explicitly state when not to use the tool but provides clear context.

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

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TDQS

A3.9/5.0

Disambiguation4/5

Despite 89 tools, each has a clearly distinct purpose with detailed descriptions that often reference related tools. Overlap exists (e.g., multiple LoRa/RF tools), but the descriptions are sufficient to distinguish them. Some confusion possible among similar-sounding tools like attenuator_pi and attenuator_tee, but the descriptions explicitly compare them.

Naming Consistency4/5

Consistent underscore-separated lowercase naming. Most tools follow a verb_noun pattern (e.g., capacitor_charge, wire_gauge) or noun_noun (power_cost). Minor inconsistencies such as 'bmi_calculator' vs 'solar_sizing' but overall predictable.

Tool Count2/5

89 tools is far too many for a single MCP server. This scope is more appropriate for multiple specialized servers. The sheer number will slow agent selection and increase cognitive load, reducing coherence.

Completeness3/5

Covers many domains (RF, solar, PCB, networking, math, etc.) but lacks depth in some areas (e.g., no three-phase power, no airflow calculations). Some domains have comprehensive coverage (LoRa/Meshtastic), but others feel incomplete for the tool count.

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