CARBON — Engineering ConfidenceUser Guide
CHAPTER 05 / 60 Pro

/carbon-functionality

Run focused CARBON Functionality testing and generate a branded functionality report.

Priya · Shopping cartStart & investigate

When to use it

You know the behavior to verify, including its edge and failure cases.

Before you start

Write down the rule before looking at implementation. For cart totals, include quantity changes, item removal and discount eligibility—not just the happy-path screenshot.

Try this in your coding agent.

/carbon-functionality Check that the cart updates quantities, discounts and totals correctly.

Replace sample paths with your project. Slash names are shorthand; your host may use a plugin prefix or a skill picker. Invocation help →

ILLUSTRATIVE WALKTHROUGH

Cart arithmetic

An expanded teaching example, not a recorded or live execution. The report stays visible while the replay explains how to read it.

  1. 01Read context
  2. 02Investigate
  3. 03Show evidence
  4. 04Report

Coding-agent conversation

Read context

I’m reviewing cart arithmetic. I’ll keep the scope and permissions explicit.

Investigate

Follow the weakest evidence link and record what remains blocked.

Show evidence

Here is the evidence trail to inspect: 2 × $12 = $24; 10% discount should be $2.40, not the previous $1.20.

Report

Changing quantity does not refresh the displayed discount. Tax rounding and multi-currency rules need separate fixtures.

CARBON

Example report

Illustration
Follow the cart state
Follow the cart state — TestBucks teaching screen

TestBucks course screen with illustrative analysis. The screenshot supplies context; the demo does not establish a newly observed bug.

  1. Cart input
  2. Totals & state
  3. Checkout evidence

Illustrated outcome

Changing quantity does not refresh the displayed discount.

Evidence to inspect

2 × $12 = $24; 10% discount should be $2.40, not the previous $1.20.

Still untested / not established

Tax rounding and multi-currency rules need separate fixtures.

Ready. Read the full example or play its steps.

What a useful result contains

A bounded claim

For cart arithmetic, state the target, revision, environment and actual work performed. Keep planned, executed, blocked and untested work separate.

An inspectable trail

2 × $12 = $24; 10% discount should be $2.40, not the previous $1.20. In a real run, retain the source, trace, screenshot or fixture behind the conclusion.

The qualification

Tax rounding and multi-currency rules need separate fixtures.

The next decision

Decide whether the evidence calls for a focused check, a reviewed fix or more context. Do not convert a plausible example into a verified finding.

Adapt the example to your project

  1. Replace cart arithmetic with a real feature, path or decision in your project.
  2. State the expected rule and its source. Include safe fixtures, constraints and a budget where appropriate.
  3. Ask for exact evidence and remaining gaps. Approve consequential actions separately.
/jay Review the /carbon-functionality result. Separate observed evidence, assumptions and untested scope, then recommend the next useful check.

Where to go next

/carbon-state →/carbon-data →

Content checked against the local command definition: skills/carbon-functionality/SKILL.md. Examples adapted from the homepage’s TestBucks walkthroughs. Availability is edition- and host-dependent.