libby 0.1.1

Radiocarbon calibration tool with LLM-powered narrative explanations, Bayesian modelling, and GIS curve selection

Libby

Modern radiocarbon calibration with LLM-powered narrative explanations, Bayesian modelling, and GIS curve selection.

Libby is a full-featured web application for calibrating radiocarbon dates with a modern Svelte 5 frontend, a Python/FastAPI backend, and unique features — including plain-English narrative explanations of calibration results, summed probability distributions, and a lat/lng-based curve selector for IntCal vs SHCal vs mixed curves.

Calibrating the Shroud of Turin (691 ± 31 BP) — from input to narrative result

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Features

• Single-date calibration — BP age + σ → calibrated PDF chart with 1σ/2σ HPD ranges
• Batch calibration — paste multiple dates at once, view SPD/KDE chart and results table
• Kernel Density Estimation (KDE) — alternative to SPD for batch date visualisation; avoids artifactual peaks from calibration curve steepness
• LLM-powered narratives — plain-English explanation of every calibration result
• Multi-language support — narratives in 12 languages (English, French, German, Spanish, Italian, Portuguese, Japanese, Arabic, Chinese, Dutch, Swedish, Polish)
• Multi-provider LLM support — Nvidia NIM (free tier, 40 req/min), Anthropic Claude
• Bayesian Phase & Sequence modelling — Metropolis-Hastings MCMC with Agreement Index (validated against known references)
• GIS curve selector — Leaflet map pin-drop auto-suggests the appropriate calibration curve based on latitude
• Marine reservoir correction (ΔR) — automatic ΔR lookup from the 14CHRONO Marine Reservoir Database (calib.org); Bevington error-weighted mean, deposit-feeder filtering, 24h cache
• Project management — group dates by site, context, or research project
• Summed Probability Distribution (SPD) — combined probability across all dates
• Taphonomic warnings — material-aware notes (old-wood effect, collagen preservation, marine reservoir effect, etc.)
• CRM report automation — generate Section 106 (US), UK HER, and generic compliance reports (PDF + DOCX)
• Export: formatted PDF report, CRM compliance reports (PDF/DOCX), CSV, OxCal CQL2 script, publication-ready text, publication-quality figures (PNG/SVG/TIFF), auto-generated journal captions
• Multi-chart output — tab-selectable chart types: interactive PDF curve, OxCal-style calibration plot (curve + measurement overlay), multi-panel publication figure (curve overview + SPD)
• Dynamic curve registry — SQLite-backed curve metadata; add new curves (IntCal25, SHCal25) by dropping .14c files into the curves directory — no code changes needed
• Calibration curves: IntCal20, SHCal20, Marine20 (CC BY 4.0)
• GIS map — OpenStreetMap with zone overlays (journal-safe, no Google Maps)
• Docker deployment and pip install packaging
• 127 tests — 64 unit (fast, no network) + 9 live calib.org integration + 54 full E2E API tests

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Tech Stack

Layer	Technology
Backend	Python 3.13+ / FastAPI
Frontend	Svelte 5 / SvelteKit / Chart.js / Leaflet
Calibration engine	iosacal + direct IntCal curve data
Bayesian MCMC	Pure numpy/scipy Metropolis-Hastings (validated)
KDE	Pure numpy/scipy Gaussian KDE (Silverman's rule)
Delta-R	calib.org on-the-fly proxy query + Bevington weighted mean
LLM	Nvidia NIM (OpenAI-compatible) or Anthropic Claude
Database	SQLite (aiosqlite) — curves, projects, calibrations, ΔR cache
PDF	ReportLab (academic + CRM reports)
DOCX	python-docx (CRM compliance reports)
Charts	Chart.js (frontend), matplotlib (figure export + PDF reports)
Curve registry	DB-backed with auto-ingestion; IntCal25-ready

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Quick Start

Install via pip

pip install libby
libby

Open http://localhost:50001 in your browser.

Run with Docker

docker compose up -d
# Open http://localhost:50001

Or pull from GitHub Container Registry (once published):

docker pull ghcr.io/mabo-du/libby:latest
docker run -p 50001:50001 ghcr.io/mabo-du/libby:latest

To publish the Docker image yourself:

docker build -t libby .
docker tag libby:latest ghcr.io/mabo-du/libby:latest
docker push ghcr.io/mabo-du/libby:latest

Build and run from source

git clone https://github.com/mabo-du/libby.git
cd libby

# Backend + frontend (single server)
uv sync
uv run uvicorn libby.main:app --reload --port 50001
# Open http://localhost:50001

# Frontend dev server (for UI development, requires backend on 50001)
cd frontend
npm install
npm run dev -- --port 50002
# Open http://localhost:50002 (points at backend API on :50001)

LLM Narratives (Optional)

Libby works without any LLM — a deterministic fallback generates coherent narratives from the numbers alone. For AI-powered narratives, set:

# Nvidia NIM (free — sign up at build.nvidia.com)
echo 'LIBBY_NIM_API_KEY=nvapi-...' > .env

# Or Anthropic Claude
# echo 'LIBBY_LLM_PROVIDER=anthropic' >> .env
# echo 'LIBBY_ANTHROPIC_API_KEY=sk-ant-...' >> .env

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Usage

Single Calibration

Enter a BP age and standard deviation, select a curve, click Calibrate. View the probability distribution chart, 1σ/2σ ranges, and plain-English narrative.

Chart types — use the tabs above the chart to switch between:

• PDF Curve — interactive probability density with hover crosshair and HPD fills
• OxCal Plot — publication-style calibration plot showing the IntCal curve with graduated uncertainty bands, your radiocarbon measurement overlaid, and the calibrated probability distribution (matching the format archaeologists expect in journal publications)
• Multi-Panel — double-column publication figure with calibration curve overview and summed probability distribution

Export options — once calibrated, download your results as:

• PNG / SVG / TIFF figures (300–600 DPI) in your selected chart type
• Journal-compliant figure caption with CC BY 4.0 curve attribution
• Publication-ready text block
• PDF report, CSV data, OxCal CQL2 script

Batch Calibration

Click Batch in the nav, paste dates as CSV-like text, calibrate all at once with Summed Probability Distribution.

GIS Curve Selector

On the calibration page, expand Curve selector by site location. Click anywhere on the map to place a pin — Libby suggests the correct curve based on latitude and explains the reasoning.

Marine Reservoir Correction (ΔR)

When calibrating marine samples against Marine20, Libby automatically looks up the local ΔR (Delta-R) correction from the 14CHRONO Marine Reservoir Database at calib.org. Enter your site coordinates and Libby:

• Queries nearby ΔR measurements within 500 km
• Filters out deposit feeders (organisms that ingest old carbonates)
• Computes the Bevington error-weighted mean and conservative uncertainty
• Displays source citations per the database's attribution requirements
• Caches results for 24 hours for speed and resilience
• Falls back to manual ΔR entry if no data is available

CRM Reports

Generate compliance-ready radiocarbon dating appendices for:

• US Section 106 (NHPA) — letter-size, regulatory language
• UK HER — A4, NPPF-compliant formatting
• Generic CRM — grey literature appendix

Output as PDF or editable DOCX. Each report includes project metadata, a date table with calibrated 2σ ranges, contextual notes, and methodology boilerplate with CC BY 4.0 curve citations.

Projects

Create projects to group dates by site. Each project shows:

• All dates with full calibration data
• Summed Probability Distribution chart
• Project summary narrative
• Bayesian modelling (Phase or Sequence)
• PDF report, publication-quality figures, OxCal export, CSV export

Bayesian Modelling

With 2+ dates in a project:

• Phase model — estimates start/end boundaries for an activity period
• Sequence model — applies stratigraphic ordering constraints
• Agreement Index (A) per date, following OxCal's convention (A ≥ 60 = acceptable)

Lab Report Import

Navigate to Import, paste CSV/TSV from your radiocarbon lab. Auto-detects columns, handles "3000±30" embedded sigma format, previews all rows, then batch-calibrates with one click.

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Project Structure

libby/
├── src/libby/              # Python backend
│   ├── main.py             # FastAPI app factory and routes
│   ├── calibration.py      # iosacal integration (async, curve-resolver)
│   ├── bayesian.py         # MCMC Phase/Sequence models (validated)
│   ├── kde.py              # Kernel Density Estimation (Silverman's rule)
│   ├── reservoir.py        # ΔR marine correction (calib.org proxy)
│   ├── crm.py              # CRM report generation (PDF + DOCX)
│   ├── narrative.py        # LLM + fallback narrative generation
│   ├── models.py           # Pydantic schemas
│   ├── database.py         # SQLite (projects, calibrations, curves, ΔR cache)
│   ├── curve_registry.py   # DB-backed dynamic curve discovery
│   ├── gis.py              # Curve suggestion by latitude
│   ├── spd.py              # Summed Probability Distribution
│   ├── export.py           # CSV/text formatters
│   ├── figures/            # Multi-chart figure generation (PDF, OxCal-style, multi-panel, KDE)
│   ├── figure.py           # Backward-compat shim → figures/
│   ├── oxcal.py            # OxCal CQL2 script export (forward-compatible)
│   ├── report.py           # Academic PDF report generation
│   ├── importer.py         # Lab report CSV/TSV parser
│   └── providers/          # LLM providers (NIM, Anthropic)
├── scripts/
│   └── ingest_curve.py     # CLI tool for registering .14c curve files
├── frontend/src/           # Svelte 5 frontend
│   ├── routes/             # Pages (/, /batch, /import, /projects)
│   └── lib/                # Components (form with ΔR panel, chart, map, etc.)
├── tests/                  # pytest (73 tests: 64 unit + 9 live)
├── docs/research/          # Deep research reports + risk assessments
├── Dockerfile              # Multi-stage Docker build
├── docker-compose.yml      # Docker deployment
└── MANIFEST.in             # PyPI package manifest

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Calibration Curves

This tool uses the internationally ratified calibration curves:

• IntCal20 — Northern Hemisphere terrestrial (Reimer et al. 2020)
• SHCal20 — Southern Hemisphere terrestrial (Hogg et al. 2020)
• Marine20 — Global marine (Heaton et al. 2020)

All curves are CC BY 4.0 licensed. Calibration engine: iosacal (GPLv3).

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Licence

MIT License. See LICENSE for details.

Citation

If you use Libby in published research, please cite:

• IntCal20: Reimer et al. 2020, Radiocarbon 62(4)
• SHCal20: Hogg et al. 2020, Radiocarbon 62(4)
• Marine20: Heaton et al. 2020, Radiocarbon 62(4)