Calcgrid

Ohm's Law Calculator

solve_ohms_law

Read-onlyIdempotent

Use this when you know two of voltage, current and resistance in a DC or purely resistive circuit and need the third and the power. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery.

Do not use this when the load is reactive (inductors or capacitors require impedance, not resistance), you want energy cost over time (use electric-power), or you need the equivalent resistance of several resistors (use resistors-series-parallel). What it computes: Solves Ohm's law V = I·R for whichever of voltage, current or resistance is omitted and reports the electrical power dissipated (P = V·I). Inputs: voltage_v (number, V, optional); current_a (number, A, optional); resistance_ohm (number, Ω, optional). Valid input combinations: Provide exactly two of voltage_v, current_a and resistance_ohm; the omitted quantity is calculated. Example: {"voltage_v":12,"resistance_ohm":220}. Complete JSON argument examples: {"voltage_v":12,"resistance_ohm":220} | {"current_a":2,"resistance_ohm":50} Outputs: solved_for, voltage_v [V], current_a [A], current_ma [mA], resistance_ohm [Ω], power_w [W]. Formula: V = I × R; I = V / R; R = V / I; P = V × I = I² × R = V² / R Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/ohms-law with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/physics/ohms-law.md

Input Schema

TableJSON Schema

Name	Required	Description
`current_a`	No	Current through the component in amperes (1 mA = 0.001 A). Omit to solve for it. Unit: A.
`voltage_v`	No	Potential difference across the component in volts. Omit to solve for it. Unit: V.
`resistance_ohm`	No	Resistance in ohms (1 kΩ = 1000 Ω). Omit to solve for it. Unit: Ω.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`links`	No
`result`	Yes
`request`	Yes
`sources`	No
`success`	Yes
`version`	No
`freshness`	No
`timestamp`	Yes
`next_actions`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedSep 26, 2026

addedInput schema / description

Added value: +"Provide exactly two of voltage_v, current_a and resistance_ohm; the omitted quantity is calculated. Example: {\"voltage_v\":12,\"resistance_ohm\":220}."

addedInput schema / examples

Added value: +[
+  {
+    "resistance_ohm": 220,
+    "voltage_v": 12
+  },
+  {
+    "current_a": 2,
+    "resistance_ohm": 50
+  }
+]

addedInput schema / oneOf

Added value: +[
+  {
+    "required": [
+      "voltage_v",
+      "current_a"
+    ]
+  },
+  {
+    "required": [
+      "voltage_v",
+      "resistance_ohm"
+    ]
+  },
+  {
+    "required": [
+      "current_a",
+      "resistance_ohm"
+    ]
+  }
+]

AddedSep 25, 2026
RemovedSep 25, 2026
First observedSep 25, 2026

TDQS

A4.6/5.0

Behavior5/5

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, and the description adds substantial behavioral context: it reports the exact output fields, substitutes current in milliamperes as well as amperes, gives the formula family used, and provides a direct REST fallback with an explicit warning not to guess another /api/* path. This goes well beyond 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.

Conciseness4/5

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

The description is longer than average but every section earns its place: usage, exclusions, computation, inputs, valid combinations, outputs, formula, fallback, and docs. It is front-loaded with the most decision-relevant guidance and uses compact formatting, though some content repeats schema examples.

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

Completeness5/5

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

For a three-parameter calculator with an output schema, the description covers everything an agent needs: when to invoke, valid input combinations, output fields, formula, direct REST fallback, and documentation. No critical operational or selection information is missing.

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

Parameters3/5

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

Schema description coverage is 100%, so the schema already documents each parameter's unit, minimum, and omission semantics. The description reinforces the 'exactly two' constraint and gives complete JSON examples, but this largely duplicates the schema rather than adding substantially new parameter meaning.

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 states a specific verb and resource: it solves Ohm's law for the missing value among voltage, current, and resistance and reports power. It clearly differentiates itself from sibling calculators by naming what it is not for (reactive loads, energy cost, equivalent resistance).

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

Usage Guidelines5/5

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

It explicitly says when to use this tool ('know two of voltage, current and resistance... need the third and the power') and instructs the agent to call it directly rather than answering from memory. It also names specific alternatives for excluded cases: use electric-power for energy cost and resistors-series-parallel for equivalent resistance.

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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