System Design
NEXUS OS Architecture
A multi-layer AI operating system built for reliability, cost-efficiency, and enterprise scale. Rust at the core, Python intelligence layer, TypeScript at the surface.
System Layers
CORTEX Router
UCB1 + EWMA routing: picks haiku/sonnet/opus per task
Budget Governor
Hard/soft token caps with APEX compression (40–70%)
Skill Library
42 composable skills across 6 domain modules
Security Gate
Automated vulnerability scanning and constitutional checks
Quality Scorer
Real-time Q-score computation from 5 weighted signals
Cost Router
Daily cron rebalances tier weights — 74% cost KPI saved
Intelligence Hub
Central registry for agent state, metrics, and knowledge
Skill Library — 6 Domains × 7 Skills
42 composable, versioned skills that agents draw from during task execution.
Backend
Frontend
Security
DevOps
Data
Intelligence
CORTEX Router
UCB1-based multi-armed bandit routing combined with EWMA quality tracking. Every task is scored for complexity, then routed to the optimal model tier — balancing quality against cost in real time.
UCB1 Routing Formula
score(tier) = Q̄(tier) + C × √(ln(N) / n(tier))
Where:
Q̄(tier) = EWMA quality score for this tier (α=0.1)
C = exploration constant (default: 1.4)
N = total routing decisions
n(tier) = decisions routed to this tier
route_tier(complexity):
if complexity < 0.75 → haiku ($0.0008/1k)
if complexity < 0.90 → sonnet ($0.003/1k)
else → opus ($0.015/1k)| Tier | Model | Cost/1k tokens | Quality Floor | Use Cases |
|---|---|---|---|---|
| haiku | claude-3-5-haiku | $0.0008 | C ≥ 0.00 | Simple CRUD, boilerplate, docs generation |
| sonnet | claude-sonnet-4 | $0.003 | C ≥ 0.75 | Feature implementation, refactoring, API design |
| opus | claude-opus-4 | $0.015 | C ≥ 0.90 | Architecture decisions, security audits, complex algorithms |
Performance Metrics
Measured across 219 calibrated sessions and live production pilots.
40–70%
APEX Compression
token reduction per session
<2ms
Avg Routing Latency
UCB1 tier selection
100%
MergeGate Pass Rate
on live toggle feature pilot
74%
Cost Reduction KPI
vs baseline (cost_router)
219
Sessions Calibrated
quality score baselines
1 → 0
Security AutoFix
cmd-injection vulns, Merge PASS
MergeGate Quality Formula
Every delivery is scored before merge
Q = 0.30 × tests_pass_rate
+ 0.25 × security_score
+ 0.20 × efficiency_score
+ 0.15 × self_correction_rate
+ 0.10 × constitution_score
Threshold: Q ≥ 0.75 → MERGE PASS
Q < 0.75 → AutoFix triggered (up to 3 attempts)
Q < 0.60 → BLOCK + human escalation