Simplest Possible Start

Simplest Possible Start

Three commands. No configuration, no GitHub login, no project directory. If you have used Claude Code on this machine, this shows what it cost.

brew tap subversivesoftwareorg/tap
brew install conscience
conscience report energy --all

What you'll see

Every Claude Code and Codex session on the machine from the last 30 days, grouped by model, with an energy estimate, its uncertainty, CO2 and water, and everyday comparisons chosen for the size of the number:

  Conscience — Energy Estimate (30 day window)

╭──────────────────┬──────────┬──────────┬───────────────┬──────────┬─────────────╮
│ Model            ┆ Tier     ┆ Sessions ┆ Output Tokens ┆ Est. Wh  ┆ Uncertainty │
╞══════════════════╪══════════╪══════════╪═══════════════╪══════════╪═════════════╡
│ claude-fable-5-1 ┆ large    ┆ 8        ┆ 13.8M         ┆ 86063.1  ┆ ±50%        │
│ claude-opus-4-6  ┆ frontier ┆ 20       ┆ 4.4M          ┆ 106414.0 ┆ ±100%       │
╰──────────────────┴──────────┴──────────┴───────────────┴──────────┴─────────────╯

  Totals
    Estimated energy: 282932.4 Wh (range: 88259–477606 Wh)
    Estimated CO2: 118.832 kg (at 0.42 kgCO2/kWh)
    Estimated water: 509.3 liters (at 1.8 L/kWh)
    Per day over 30 days: 9431 Wh, 3.961 kg CO2, 17.0 L water

  Equivalent to (illustrative)
    Energy  ≈ 9.6 days of a US household's electricity (3–16)
            source: EIA 2022, 10,791 kWh per household per year
    CO2     ≈ 297 miles of gasoline-car driving (93–501)
            source: EPA average passenger vehicle, 404 g CO2 per mile
    Water   ≈ 7.8 showers (2.4–13)
            source: EPA WaterSense, 8 minutes at 2.1 gallons per minute

Every figure is an estimate from published research, shown with its range and its source. No provider publishes official numbers. The caveats printed under the table say exactly what the estimate does and does not cover.

Why this command first

• It reads only what is already on your machine: Claude Code's logs under ~/.claude/projects/ and Codex's under ~/.codex/sessions/. Nothing is sent anywhere.
• It needs no GitHub token and no conscience.yaml.
• --all means every project, so it works from any directory.

If it says no sessions were found, you haven't used Claude Code or Codex on this machine yet, or their logs live somewhere else.

The next two steps

From inside a project you work on with AI tools:

cd ~/code/your-project
conscience examine

The current directory is the project and its origin remote is the repository, so still no flags. You get what was analyzed, what deserves attention, and one question worth discussing. Then, when you want the questions with your team:

conscience reflect --interactive

Getting Started walks through both with the optional pieces: GitHub login, conscience.yaml, and CI.

Other ways to install

cargo install conscience    # any platform with Rust

Or download a binary from the releases page.