The framework-agnostic core of USRCP — the encrypted ledger, crypto, device pairing, identity rotation, and scope enforcement, with no MCP server and no CLI.

usrcp-core is the protocol engine every other USRCP package builds on. It has no opinion about how it's driven — the local MCP server (usrcp-local), the capture adapters, and usrcp-stream all depend on it for the same encrypted, structured user state. Its only runtime dependencies are better-sqlite3 and zod.

If you just want to run USRCP, install usrcp (npm i -g usrcp) or brew install frank-bot07/usrcp/usrcp — you don't install usrcp-core directly. This package is for building on the protocol.

What's in it

Encrypted ledger (usrcp-core/ledger) — a single SQLite file where every value is encrypted at rest (libsodium secretbox) under a master key that never leaves the machine. Structured facts, timeline events, domain context, audit log.
Encryption + crypto (usrcp-core/encryption, usrcp-core/crypto) — master-key derivation, per-domain keys, HMAC blind-index search tokens, identity keypair management.
Device pairing (usrcp-core/pair) — the pairing protocol (the terminal QR rendering lives in usrcp-local, not here).
Identity rotation (usrcp-core/rotate-identity).
Scope enforcement (usrcp-core/scope-enforcement) — default-deny read projections and per-tool scoping, shared so usrcp-local and usrcp-stream enforce identical semantics.

Install

npm install usrcp-core

better-sqlite3 is a native module; it builds on install.

Subpath exports

import { Ledger } from "usrcp-core/ledger";
import { encrypt, decrypt, deriveDomainEncryptionKey } from "usrcp-core/encryption";
import { getIdentity } from "usrcp-core/crypto";
import { pairInit, pairJoin } from "usrcp-core/pair";
import { rotateIdentity } from "usrcp-core/rotate-identity";
import { registerToolsWithScopes } from "usrcp-core/scope-enforcement";

The barrel (usrcp-core) re-exports all of the above.

What it is not

Not the MCP server. That's usrcp-local (which depends on this).
Not a CLI. No usrcp command here — that's usrcp-local.
Not a semantic memory layer. USRCP stores structured, exact-match user state; it does not do vector/embedding recall. See the main README.