Xraylarch

MCP (Model Context Protocol) server that wraps xraylarch for X-ray spectroscopy analysis. Load, process, analyze, and plot XAS/XAFS spectra through Claude Desktop or Claude Code with natural language tool calls. Supports XANES normalization, EXAFS extraction, Fourier transforms, linear combination fitting, PCA, FEFFIT shell fitting, and publication-quality plotting.

Installation

pip install xraylarch-mcp

Configuration

Claude Desktop

Add to your Claude Desktop configuration (claude_desktop_config.json):

{
  "mcpServers": {
    "xraylarch": {
      "command": "python",
      "args": ["-m", "xraylarch_mcp"]
    }
  }
}

Claude Code

claude mcp add xraylarch -- python -m xraylarch_mcp

Quick Start

Ask Claude:

"Load the spectrum at ~/data/fe_foil.xdi and show me the normalized XANES"

Claude will:

1. Call larch_load_spectrum to read your data
2. Call larch_normalize to perform pre-edge subtraction and normalization
3. Call larch_plot with plot_type="norm" to generate a publication-quality plot

Tool Reference

I/O Tools

Tool	Description
larch_load_spectrum	Load a spectrum from file (.xdi, .dat, .csv, .prj, etc.)
larch_read_athena_project	Read/inspect Athena project files
larch_list_groups	List all loaded spectrum groups
larch_inspect_group	Detailed view of a group's arrays and scalars
larch_remove_group	Remove a group to free memory

XAFS Analysis Tools

Tool	Description
larch_normalize	Pre-edge subtraction and normalization (wraps pre_edge)
larch_autobk	EXAFS background removal (AUTOBK algorithm)
larch_xftf	Forward Fourier transform: chi(k) -> chi(R)
larch_xftr	Back Fourier transform: chi(R) -> chi(q)
larch_fluo_corr	Fluorescence self-absorption correction
larch_mback_norm	MBACK normalization (alternative for problematic data)
larch_estimate_noise	Noise estimation in chi(k) and chi(R)
larch_cauchy_wavelet	Cauchy wavelet transform for simultaneous k- and R-resolution
larch_rebin	Rebin to standard 3-region XAFS energy grid

Plot Tools

Tool	Description
larch_plot	Publication-quality plots (mu, norm, flat, dmude, chi_k, chi_r, chi_q, cauchy_wavelet)

Math Tools

Tool	Description
larch_smooth	Smooth arrays with Lorentzian/Gaussian/Voigt kernel
larch_deriv	Numerical derivative
larch_interpolate	Interpolate onto new energy grid
larch_merge_groups	Merge/average multiple spectra
larch_deglitch	Remove glitch points

Fitting Tools

Tool	Description
larch_lcf	Linear combination fitting against standards
larch_pca	Principal Component Analysis
larch_feffit	FEFFIT EXAFS shell fitting
larch_peak_fit	Peak fitting (Gaussian, Voigt, etc.)

Interactive Tools

Tool	Description
larch_interactive_norm	Open an interactive HTML page to tune normalization parameters
larch_apply_norm_params	Apply normalization parameters from a saved JSON file

Interactive normalization workflow

1. Ask Claude to interactively normalize your spectrum
2. An HTML page opens in your browser with Plotly.js plots and sliders
3. Adjust E0, pre-edge range, post-edge range, and polynomial degree — plots update in real time
4. Click Save Parameters to download a JSON file, or Copy to Clipboard
5. Tell Claude to apply the saved parameters

"Load Pdfoil.prj and let me interactively choose the normalization parameters"

Advanced

Tool	Description
larch_run_code	Execute arbitrary Python code in the larch session

Resources

The server exposes documentation resources that Claude can read on demand:

• larch://docs/xafs — XAFS analysis reference
• larch://docs/io — I/O functions reference
• larch://docs/fitting — Fitting reference
• larch://docs/feff — FEFF interface reference
• larch://docs/interactive — Interactive tools reference
• larch://docs/examples/xanes — XANES workflow example
• larch://docs/examples/exafs — EXAFS workflow example

Links

• xraylarch documentation
• MCP specification
• Source code

License

BSD-3-Clause (matching xraylarch)