RETICOLO MCP — RCWA Solver via MATLAB Engine API

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MCP server for the RETICOLO V10 rigorous coupled-wave analysis (RCWA) solver. Wraps MATLAB R2025b via the Engine API.

Quick start

# 1. Create conda env
conda create --name reticolo-mcp python=3.11 -y
conda activate reticolo-mcp

# 2. Install dependencies
pip install mcp numpy pydantic

# 3. Install MATLAB Engine API (one-time)
cd "D:\Program Files\MATLAB\R2025b\extern\engines\python"
pip install .

# 4. Install this package
pip install .

# 5. Set RETICOLO path and run
$env:RETICOLO_MCP_DIR = "D:\RETICOLO V10\V10_2025\reticolo_allege_v10"
python -m reticolo_mcp.server

opencode / Codex MCP config

{
  "reticolo": {
    "type": "local",
    "command": ["D:\\condaenvs\\reticolo-mcp\\python.exe", "-m", "reticolo_mcp.server"],
    "environment": { "RETICOLO_MCP_DIR": "D:\\RETICOLO V10\\V10_2025\\reticolo_allege_v10" },
    "enabled": true,
    "timeout": 120000
  }
}

Tools

Tool	Status	Description
solver_status	✓	Lease state + COMSOL collision check (read-only, no MATLAB)
reticolo_start	✓	Start MATLAB engine, acquire lease, M0 disk-safety
reticolo_stop	✓	Stop engine, release lease, clean scratch
reticolo_status	✓	Engine state + lease status
reticolo_solve_point	✓	One wavelength → R, T, A_balance, passive
reticolo_sweep	✓	Resumable sweep, flush+fsync CSV, config_hash resume
reticolo_convergence	✓	Progressive nn scan, peak tracking, FWHM, Q
reticolo_field_export	✓	Field export via retchamp, slice-plane, NPZ output
job_submit	✓	Submit durable staged-sweep job
job_status	✓	Read job state + progress
job_tail	✓	Last N events from job journal
job_cancel	✓	Cooperative cancel request (between solve points)
job_resume	✓	Resume failed/interrupted job

✓ = verified against real RETICOLO V10 + MATLAB R2025b (2026-07-13).

Verification

Gate	Evidence
G0 — Engine lifecycle	Start → health → stop, no MATLAB leak, no orphans
G1 — M0 resource	nn=9×2 + nn=15×1, C: Δ=0 GB, no retXXXX orphans, memory mode
G2 — Numerical baseline	TE slab n=1.5: R=0.147929 vs analytical 0.1479 (0.03% err); lossy slab passive ✓
G3 — Durable jobs	Worker → results match G2; resume skips completed rows
Unit tests	133 passed (import safety, config, schema, engine, lease, sweep, jobs, hash, convergence, field_export, worker, server)
G0 — Engine lifecycle	Start → health → stop, no MATLAB leak, no orphans (MCP verified 2026-07-13)
M3 — High-order smoke	nn=21 (32s) + nn=31 (261s), memory-mode stable, no OOM
M4 — Scratch mode	solves correctly, matches memory-mode results

Known limitations

• TM at normal/off-normal incidence: pol=-1 gives R=T=0 for symmetric structures due to RETICOLO V10 field-decomposition degeneracy. Use off-normal with delta0≠0 or investigate ef.TMinc_top_* channels.
• Field export (retchamp): RETICOLO V10 retapod/retchamp crashes on uniform structures with an imag(apod) type error. This is an upstream V10 bug; field export is unverified until a workaround or V10 patch is available.

⚠ Disk safety

RETICOLO's internal retio system spills large matrices to retXXXX/ scratch directories during high-order scans. This server defaults to memory mode (vmax=inf, no disk spill). MATLAB temp files are redirected to D:\matlab_temp.

Startup applies:

• retio([], inf*1i) — disable scratch writes
• TMP/TEMP/TMPDIR → D:\matlab_temp
• Working directory → D:\reticolo_scratch
• Lease with COMSOL MCP collision detection

Configuration

The server requires an external RETICOLO V10 installation. The bundled reticolo_v10/ directory in the repository is for development only and is not included in the PyPI wheel (CC-BY 4.0 — separate from the MIT wrapper).

$env:RETICOLO_MCP_DIR = "D:\RETICOLO V10\V10_2025\reticolo_allege_v10"
python -m reticolo_mcp.server --reticolo-dir "D:\RETICOLO V10\V10_2025\reticolo_allege_v10"

Architecture

reticolo-mcp/
├── src/reticolo_mcp/
│   ├── server.py        # FastMCP server, all tools
│   ├── engine.py        # MATLAB Engine lifecycle + solve
│   ├── lease.py         # Atomic solver lease (named mutex)
│   ├── sweep.py         # Resumable sweep + peak analysis
│   ├── jobs.py          # Durable job store (spec/state/events)
│   ├── worker.py        # Detached worker process
│   ├── convergence.py   # Progressive harmonic convergence
│   ├── field_export.py  # retchamp field export
│   ├── schema.py        # Pydantic models for materials/geometry
│   ├── config_hash.py   # Canonical SHA-256 config identity
│   └── config.py        # Paths, limits, env vars
├── reticolo_v10/        # Bundled RETICOLO V10 (CC-BY 4.0, dev only)
├── tests/               # Unit + integration tests
├── pyproject.toml
├── LICENSE              # MIT (wrapper code)
├── NOTICE               # CC-BY 4.0 attribution
└── README.md

License

• MCP wrapper code (all Python files): MIT License.
• Bundled RETICOLO V10 (reticolo_v10/): CC-BY 4.0, © Jean Paul Hugonin & Philippe Lalanne. DOI: 10.5281/zenodo.14631951.

See LICENSE and NOTICE for details.