Inform by default; gate only by explicit opt-in. Energy numbers inform. The one exception is a budget the user set with ENERGY_BUDGET_MODE=restrict, chosen eyes-open in the interview — then the gate is theirs, and the honesty burden doubles: they are being governed by a floor estimate on purpose, and every refusal says so.
Cited figures only, provenance inline. The two published anchors, with what they cover:
- ~0.24 Wh — Google's published median for a Gemini Apps text prompt (2025). Includes accelerator, host CPU/memory, backup equipment, and datacenter overhead including cooling; excludes training.
- ~0.34 Wh — OpenAI's figure for an "average" ChatGPT query (2025, from Sam Altman's blog). Not peer-reviewed; "average query" is undefined.
Both are vendor self-reported. Say so when asked.
Never invent a conversion. There is no published per-token energy figure — do not create one. Nobody has published figures for agentic coding sessions either; they involve far more computation per turn than a median chat prompt, which is exactly why every estimate here is a floor.
No shame mechanics. The footer is information; the budget is theirs; crossing it changes what you say, never what you do.

Estimating: count turns, multiply, call it a floor

A "turn" is one model call — each response, including each tool-use step in an agentic session, is one. Turns are countable; per-turn cost is not knowable, so:

estimated floor = (turns you can count) × 0.24 Wh (the conservative anchor)

The footer shows only the result (see Rendering); the method stays one question away — when they ask "how was this measured", give the math, the turn count, and both anchors with provenance. When you cannot count turns on a surface, estimate the count conservatively and say you did. Never present a result without its floor marker: a trailing + on the number (36+ Wh), which reads naturally and stays true — the real cost is higher, never lower.

Rendering: keep it light

One terse line, emoji that scale with the magnitude, no method talk. End-of-session footer (only when ENERGY_FOOTER=yes in ~/.config/ai-limits/config, or on request; skip it in automated sessions):

💡💡💡💡💡💡 6+ Wh this session · lights on for ~40 min

At bigger totals, switch units so the emoji stay meaningful:

📱📱📱 51+ Wh this week · 3 full phone charges · lights on for ~5 hours

Rules:

The number: counted turns × 0.24 Wh, rounded, with a trailing + carrying the floor.
💡 one per Wh, capped at ten. 📱 one per full phone charge (~15 Wh), capped at ten — use phones once bulbs stop being legible.
Felt equivalents: lights-on time = Wh ÷ 10 W LED; a phone charge ≈ 15 Wh. Month- and year-scale equivalences (✈️ flights and beyond) need cited energy-to-carbon conversions — that's the energy tracker's job, not this footer's.
Nothing else on the line. Method and provenance are answers, not furniture.

Like everything text-shaped, the footer is advisory on every surface (see the enforcement matrix in limits-setup). It works by being followed.

The weekly budget (optional, three modes)

The interview offers four paths; config records them:

Choice	Config	Behavior
No thanks	`ENERGY_FOOTER=no`	Energy never comes up
Inform only	footer on, no budget	The footer, nothing else
Budget + warn	`ENERGY_BUDGET_MODE=warn`	Crossing the budget gets exactly this, once per week, and nothing more: "🌍 FYI, you've exceeded your weekly energy budget of Wh."
Budget + restrict	`ENERGY_BUDGET_MODE=restrict`	The `energy-gate.sh` hook refuses further prompts once the week's floor crosses the budget — terse, identical, overridable through a deliberate typed act (don't volunteer the command; tell them if they ask)

The budget week is fixed: it starts Monday at the day boundary (default 4AM) and resets the following Monday — a reset you can name, not a rolling window that follows you around.

Always, whenever the footer is on — budget or not:

Where a filesystem exists, append one line per session to ~/.config/ai-limits/state/energy-ledger.log: 2026-08-27 wh=2+ turns=8 <one-word context> — keep this format stable and parseable; it is the data source for the budget math, the weekly report, and the first-week baseline a person sets their budget against.
Useful scale for picking a number: a full smartphone charge is roughly 15 Wh; an hour of a 10 W LED is 10 Wh; a published chat prompt is about a quarter of a watt-hour.
Restrict mode's honest label: it is the softest of the kit's three gates. Quiet hours read the clock; the session gate reads hook-written state; this gate reads a ledger the AI itself writes at session ends — real enforcement fed by best-effort data. The user chose it knowing the numbers are floors, not measurements; never let a refusal pretend otherwise.

The baseline review

When the config has ENERGY_FOOTER=yes and no ENERGY_BUDGET_WH_WEEK, and the ledger holds a week of data: the next limits/energy report opens with the baseline — the week's floor total, rendered honestly — and asks them to set their budget number against it (and the enforcement mode, if 5b recorded "not sure"). This is the one moment the kit proactively asks; it isn't a nag — it's the appointment their own 5a answer scheduled. If they defer, defer; ask again only at the next report they request.

Weekly report

When asked ("energy report", or as part of a limits report): sum the ledger's ranges, render the lightbulb row, compare to the budget if one is set, and state what the number is: a floor estimate of one slice of the true cost — it excludes training, embodied hardware, idle capacity, and anything the providers don't publish. Never let the report imply completeness it doesn't have; where the ledger has gaps, say "not measured" rather than backfilling.

limits-energy

Limits: energy

The honesty contract (binding on you, the agent)