soif 💧

soif — French for thirst.

Estimate the water footprint of LLM prompts, the way you estimate their cost.

Every LLM answer evaporates real freshwater: data-center cooling towers (on-site) and the power plants feeding them (off-site) both consume it. Published per-prompt figures span two orders of magnitude — Google measured 0.26 mL per median Gemini prompt, while Mistral's lifecycle analysis reports 45 mL per 400-token Large 2 response. soif turns model + tokens + hosting assumptions into an honest low / mid / high water estimate with a fully documented, versioned methodology (METHODOLOGY.md).

• Pure Python, zero runtime dependencies, MIT-licensed.
• Library API, CLI, SDK response adapters (OpenAI / Anthropic), a Claude Code hook, and water-aware model routing for agent graphs.

📚 Docs: unchained-labs.github.io/soif

Install

pip install soif-llm                 # imports as `soif`; from a checkout: pip install .
pip install "soif-llm[tokenizers]"   # optional: exact token counts via tiktoken

(The PyPI distribution is soif-llm — the bare name was taken — but the module is soif.)

Quick start

import soif

est = soif.estimate("gpt-4o", prompt="Explain retrieval-augmented generation.")
print(est.humanize())
# ~1.15 mL of water (23.0 drops); range 0.113 mL - 12.46 mL

est.total_ml.mid        # millilitres, mid scenario
est.onsite_ml           # cooling-tower evaporation at the data center
est.offsite_ml          # water consumed generating the electricity
est.embodied_ml         # amortised manufacturing (chips, servers, buildings)
est.assumptions         # every default the estimate leaned on, spelled out

The accurate path is to feed real token usage from an API response — this captures actual output length, reasoning ("thinking") tokens, and cache hits:

response = client.chat.completions.create(...)   # OpenAI — or Anthropic messages.create
est = soif.from_response(response)

Reasoning models drink more — thinking tokens are output tokens:

soif.estimate("gpt-5", output_tokens=500, reasoning_effort="high")
soif.estimate("o3", output_tokens=500, reasoning_tokens=8000)   # from real usage

Control the hosting scenario:

soif.estimate("llama-3.1-70b", output_tokens=500,
              provider="aws", region="nordics",      # presets
              include_embodied=False)                # operational water only
soif.estimate("my-fine-tune", active_params_b=8, wue=0.2, pue=1.12, ewif=0.4)

CLI

soif estimate "why is the sky blue?" --model claude-sonnet-4-5
soif estimate -m gpt-4o -i 1200 -o 500 --json
soif compare gpt-4o gpt-4o-mini gemini-2.5-flash claude-haiku-4-5 -o 500
soif models

Agent graphs: metering and minimising water across a chain

Two primitives make water a first-class optimization target in agentic pipelines (LangGraph, hand-rolled DAGs, anything):

1. Meter — accumulate across nodes, with a soft budget:

meter = soif.Meter(budget_ml=50)

def summarize_node(state):
    resp = client.chat.completions.create(model=state["model"], ...)
    meter.record(soif.from_response(resp))
    if meter.over_budget:
        state["model"] = "gpt-4o-mini"   # degrade later hops
    return state

print(meter.summary())
# 7 call(s): ~18.2 mL of water (3.7 teaspoons); range ... — within budget (18.2/50.0 mL)

2. soif.optimize — route each node to the least-thirsty capable model:

from soif import optimize

optimize.pick_model(
    ["gpt-4o", "gpt-4o-mini", "gemini-2.5-flash", "claude-sonnet-4-5"],
    min_tier="small",              # capability floor for this node
    input_tokens=2000, output_tokens=300,
)
# -> 'gemini-2.5-flash'... whichever mid-scenario estimate is lowest

optimize.savings("claude-opus-4", "claude-haiku-4-5", output_tokens=500)
# {'baseline_ml': ..., 'alternative_ml': ..., 'saved_ml': ..., 'saved_pct': ...}

Model choice is the big lever (~30× between tiers); after that: shorter outputs, prompt caching, modest reasoning effort, and low-water regions/providers.

Claude Code hook

Get a water read-out for every session, computed from the transcript's real token usage — see integrations/claude-code. In short, add to .claude/settings.json:

{
  "hooks": {
    "Stop": [
      { "hooks": [{ "type": "command", "command": "soif claude-hook" }] }
    ]
  }
}

After each turn: soif: this session used ~4.31 mL of water (0.9 teaspoons); range ... across 12 model call(s).

How it works (short version)

E_it       = tokens × Wh-per-token(model tier)        # server energy
E_facility = E_it × PUE                               # + cooling/power overhead
W_onsite   = E_it × WUE                               # cooling evaporation
W_offsite  = E_facility × EWIF                        # power-plant water
W_total    = (W_onsite + W_offsite) × lifecycle       # + embodied (optional)

Every factor is a (low, mid, high) triple propagated end-to-end, so the range reflects genuine uncertainty rather than false precision. Factors are versioned (soif.factors.FACTORS_VERSION) and calibrated against Google's measured Gemini numbers, Epoch AI's GPT-4o analysis, Mistral's Large 2 LCA, and Ren et al.'s methodology. Read METHODOLOGY.md before quoting numbers — these are estimates, not measurements.

Contributing

Factor updates (new disclosures, better WUE/PUE/EWIF data, new models) are the most valuable contributions — please include sources. pip install -e ".[dev]" && pytest && ruff check .

License

MIT