marl-book-mcp

An MCP server that exposes the full text of Multi-Agent Reinforcement Learning: Foundations and Modern Approaches by Stefano V. Albrecht, Filippos Christianos, and Lukas Schäfer (The MIT Press, 2024), so an LLM can search it, pull a specific page, or read a whole chapter instead of guessing from memory.

Built with FastMCP. Runs locally over stdio, or as a remote HTTP server with OAuth for clients like claude.ai. Modeled on the sibling rlbook/ server (Sutton & Barto).

Licensing: the code is MIT. The book text under pages_corrected/ and the raw OCR under ocr_raw/ is not — it belongs to the authors and MIT Press. Read NOTICE.md before you reuse anything from those directories.

Tools

Math is returned as LaTeX (inline \( … \), display \[ … \]), reconstructed from the Nougat OCR pass.

Related MCP server: AI Book Agent MCP Server

The corpus and how it was built

The book PDF is freely available (color, ~8 MB) at https://www.marl-book.com (the "Download" link). It is a native-text PDF, but a plain PyMuPDF extraction flattens all the mathematics. To keep the equations, the corpus was built with a two-source OCR + reconciliation pipeline (same idea as rlbook/, but the source here is digital rather than scanned):

1. PyMuPDF (extract.py) — faithful running text, used as the spelling / wording reference. Output in ocr_raw/pymupdf_pages_*.txt.

2. Nougat (run_nougat.py, run on the dataia25 GPU cluster, 2× RTX 3090) — math-aware OCR producing LaTeX. Output in ocr_raw/nougat_pages_*.mmd.

3. Reconciliation — every page was cross-checked between the two sources and hand-corrected into pages_corrected/pages_XXX-YYY.md (10–14 pages/file, --- PAGE N --- separators, N = PDF page). Section numbers Nougat dropped were restored, all algorithm boxes and linear programs were reconstructed, figures are described in-line as [Figure N.M: …], and Nougat runaway/repeat pages (191, 283, 37, …) were rebuilt from PyMuPDF.

pages_corrected/ is what the server actually reads via _load_all_pages(). References (p.370–391) and the index (p.392–395) are included from the PyMuPDF text. The source PDF is gitignored (*.pdf) — download it yourself if you want to re-extract.

Nougat on the cluster (gotchas)

Nougat 0.1.17 is abandoned and hostile to modern Python. The working recipe (isolated venv, py3.12) pins around it:

• transformers==4.34.1 (5.x → NameError: name 'nn' is not defined)

• albumentations==1.3.1 (2.x changed the ImageCompression signature)

• pypdfium2==4.20.0 (≥4.25 removed PdfDocument.render)

• install nougat-ocr --no-deps after the pinned wheels (its datasets[vision] otherwise backtracks to an ancient pyarrow sdist that won't build on 3.12)

• sentencepiece is required but not pulled in with --no-deps.

Drive it page-by-page with batch_size=1 (run_nougat.py) so page↔prediction alignment is guaranteed and --- PAGE N --- markers are exact.

Chapter map (PDF page ranges)

Front matter 1–29 · Ch1 30–45 · Part I 46–47 · Ch2 48–71 · Ch3 72–89 · Ch4 90–117 · Ch5 118–143 · Ch6 144–187 · Part II 188–189 · Ch7 190–211 · Ch8 212–247 · Ch9 248–333 · Ch10 334–347 · Ch11 348–365 · Appendix A 366–369 · References 370–391 · Index 392–395.

Run

Local (stdio)

python -m venv .venv && source .venv/bin/activate
pip install -r requirements.txt
python server.py

Register with Claude Code:

claude mcp add marlbook -- /home/bnj/mcp_servers/.venv/bin/python /home/bnj/mcp_servers/marlbook/server.py

Local editor integrations (Continue, Zed, …)

Loopback, no auth:

python server.py --http --no-auth --port=8008

--no-auth binds to 127.0.0.1 and refuses any other host. Do not put this mode behind a reverse proxy — use OAuth for anything off-machine. See continue-mcp.yaml.

Remote (HTTP + OAuth)

Copy .env.example to .env and fill it in (MCP_CLIENT_SECRET from openssl rand -hex 32, a MCP_ACCESS_PIN, and the public MCP_BASE_URL). Then:

set -a && source .env && set +a
python server.py --http --port=8008

Deployed here as the systemd user service mcp-marlbook.service on port 8008, behind Caddy on the rpi5 (mcp-marlbook.benjamin-lepourtois.fr, flush_interval -1 for SSE), with a Hostinger A record and the connector registered on claude.ai.

Known limitations

• Page numbers are PDF-relative (printed number = PDF − 29).

• Figures are described, not reproduced — schematics, learning curves, and matrix-game diagrams are summarized in brackets from their captions.

• Search is literal (term counts, no stemming/semantics).

• OCR is imperfect on the densest equations and tables; a handful of Nougat runaway pages were rebuilt from PyMuPDF and are marked as such.

Credits

The book is by Stefano V. Albrecht, Filippos Christianos, and Lukas Schäfer, published by The MIT Press. This repository only wraps its text in an MCP interface. See NOTICE.md.