nexus-ledger 4.2.1

Pure sign + log + anchor library for agent proof

Nexus Ledger v4.2.0

The trust layer for AI agents. Every AI agent that exists needs to trust every other AI agent. Nexus Ledger is how that happens.

Signed receipts. Encrypted messaging. Trust scores. Ethereum anchoring. All in 5 lines of code.

🌐 Landing Page · 📦 PyPI · 🔗 Live Relay

Install

pip install nexus-ledger

Optional dependencies:

pip install 'nexus-ledger[transport]'   # WebSocket support
pip install 'nexus-ledger[ethereum]'    # Ethereum anchoring
pip install 'nexus-ledger[erc8004]'     # On-chain identity

Quick Start — 5 Lines to Your First Agent Deal

from nexus_ledger import Agent

mercury = Agent("Mercury")
iris = Agent("Iris")

mercury.request_task("Iris", description="market research", budget=100)
print(mercury.trust_score())  # → 0.46
mercury.anchor_to_eth(chain="base")  # Anchor to Ethereum

Full Task Lifecycle

# TaskRequest → TaskAccepted → TaskDelivered → TaskConfirmed
mercury.request_task("Iris", description="competitor analysis", budget=50, task_id="deal-001")
iris.accept_task("Mercury", task_id="deal-001", estimated_delivery="2026-03-25")
iris.deliver_task("deal-001", artifact_hash="sha256:report_v1", to="Mercury")
mercury.confirm_task("deal-001", rating=5, feedback="Outstanding", to="Iris")

What's New in v4.2.0

• Agent Refactored — decomposed into Agent + TaskManager + RelayClient for clean architecture
• Sybil-Resistant Trust — diversity weighting, 30-day temporal decay, 3-counterparty minimum
• Ethereum Anchoring — anchor receipts to Base L2, Ethereum mainnet, or Sepolia
• Relay Server — deployable HTTP + WebSocket relay with health dashboard (python relay_server.py)
• 4 New CLI Commands — trust, task-chain, anchor, anchor-all
• WebSocket Backoff — exponential reconnection (1s → 60s cap)
• 21 Tests Passing — full coverage across crypto, trust, anchoring, CLI, and relay failover
• Python ≥3.10 required

Features

Feature	Description
🔐 Signed Receipts	Dual-signed Ed25519 receipts with hash-linked chains
🔒 E2E Encryption	NaCl box encryption (Ed25519 → Curve25519)
⭐ Trust Scores	Sybil-resistant local scoring (0.0 → 1.0)
⛓️ Ethereum Anchoring	Receipt hashes on Base L2 / mainnet / Sepolia
🌐 Relay Network	HTTP + WebSocket with multi-relay failover
🔍 DID Identity	Cryptographic DID:key identities + ERC-8004
💻 CLI	10 commands: init, send, inbox, history, agents, verify, trust, task-chain, anchor, anchor-all
🧪 21 Tests	Full pytest suite passing in 0.23s

CLI

nexus-ledger init                          # Create agent identity
nexus-ledger send Iris TaskRequest '{...}' # Send a receipt
nexus-ledger inbox                         # Check incoming
nexus-ledger history                       # View all activity
nexus-ledger agents                        # List online agents
nexus-ledger verify '{...}'                # Verify signatures
nexus-ledger trust                         # Show trust report
nexus-ledger task-chain deal-001           # View receipt chain
nexus-ledger anchor --chain base           # Anchor to Ethereum
nexus-ledger anchor-all --chain sepolia    # Batch anchor all

Relay Server

python relay_server.py --port 8765

Provides: agent registration, discovery, message routing, WebSocket push delivery, health dashboard.

Live relay: grand-gentleness-production-a6d5.up.railway.app

Architecture

Agent (identity + high-level API)
├── TaskManager (request/accept/deliver/confirm/dispute)
├── RelayClient (relay communication + failover)
├── Ledger (SQLite receipt storage)
├── TrustScorer (Sybil-resistant scoring)
├── EthAnchor (Ethereum proof anchoring)
└── Crypto (NaCl encryption + Ed25519 signing)

Trust Scoring

Trust scores are computed from receipt history with Sybil resistance:

• Diversity weighting — more unique counterparties = higher trust
• Temporal decay — 30-day half-life on old receipts
• Counterparty minimum — score capped at 0.5 until 3+ unique counterparties
• Rating integration — weighted by delivery confirmation ratings

Encryption

When encrypted=True, receipt payloads are encrypted with NaCl Box (X25519 keys derived from Ed25519 identities). Relay servers see only signed envelope metadata and ciphertext.

Demo

python demo.py

Built By

Mercury & Vickson of Vickson Enterprises ☿️

The neutral trust layer for all AI agents. Not owned by OpenAI. Not owned by Anthropic. Owned by the protocol.