Engine MCP Server

Microtoll Engine

The security layer of an end-to-end-encrypted app, as packages that give any app the four things AI-generated apps get wrong: sign-in, key handling, access control and revocation. The server stores only what it cannot read.

Status: 0.1.0, the first release (2026-09-27). Pre-1.0: function names and options may change between minor versions; the bytes it writes never will. See docs/pages/formats-and-stability.md.

Each package carries its own LICENSE. Documentation is CC-BY-4.0.

Documents

• THREATMODEL.md — per-package threat models and honest limits.
• docs/ — the source of microtoll.dev, llms.txt and the MCP snapshot (npm run docs).
• Each package's FORMATS.md or DESIGN.md — its formats, byte for byte.
• SECURITY.md, CONTRIBUTING.md — how to report a weakness; the rules and the sign-off.

References such as "D-04" in code comments and changelogs are to the maintainer's decision log, which is kept privately.

Examples and deployment

• examples/notes-app — end-to-end-encrypted notes with sharing and revocation on the reference server: docker compose up, then http://localhost:8088.
• examples/identity-demo — the identity package on a page against its in-process server stand-in.
• deploy/ — the hardened Compose file, the Dockerfile and the Nginx sample for blind-store.

How it was built, and support

The engine was written with Claude Code (Anthropic's coding agent) from a security design the maintainer wrote and decided; the maintainer read and accepted every change and recorded every decision with its reasons. The checks are the ones you can run: the published test vectors (RFC 5869, RFC 8032, RFC 5903, RFC 7914, NIST CAVP, the X-Wing draft) through the public API, the frozen fixtures, the adversarial suite, and the threat model written down in THREATMODEL.md. An outside security audit is the next step.

The packages are free and stay free. If they save you work, you can sponsor the work on GitHub.

Working on it

npm install          # TypeScript for the declaration check; ws and pg for blind-store
npm run check        # typecheck + tests (Node >= 24)
npm run db:up        # a throwaway Postgres 17 in Docker for the database-backed suites

Tests use Node's built-in node:test. The browser packages have no runtime dependencies; blind-store has exactly ws and pg. The suites that need a database (blind-store's schema, protocol, live and fixture checks, and the notes example) run when npm run db:up has started one — or a Postgres answers at BLIND_STORE_TEST_DB — and skip with one line otherwise; CI runs them.