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Key Terms Glossary

Quick reference for CitadelMesh concepts and terminology

Core Concepts​

Agent​

A software program that perceives its environment, reasons about what to do, acts to achieve goals, and learns from results. CitadelMesh has Security, Energy, and Orchestrator agents.

Multi-Agent System​

Multiple specialized agents working together, each expert in their domain, coordinated by an orchestrator.

Policy​

A rule that agents must follow, enforced by OPA. Example: "Cannot lock emergency exits when building is occupied."

Zero-Trust Safety​

Security principle where every agent action must be validated by policies - nothing is trusted by default.

Technologies​

OPA (Open Policy Agent)​

Policy engine that validates every agent action. Uses Rego language for policies. Ensures agents can't perform unsafe operations.

MCP (Model Context Protocol)​

Standard interface for integrating vendor systems. Allows agents to control doors, cameras, HVAC regardless of manufacturer.

SPIFFE/SPIRE​

Zero-trust identity system. Gives each service a cryptographic identity (SVID). No passwords or API keys.

CloudEvents​

Standard format for events. Describes what happened (type, source, data) in a consistent way.

LangGraph​

State machine framework for building agents. Defines how agents transition between MONITOR → ANALYZE → DECIDE → ACT states.

NATS​

Message bus for event-driven communication. Agents publish events, subscribe to events from other agents.

Architecture Terms​

Edge-First​

Running software at the building (edge) rather than in the cloud. Provides low latency, privacy, and works offline.

Orchestrator​

The "conductor" that coordinates multiple agents. Resolves conflicts using priority hierarchy (Safety > Security > Comfort > Cost).

State Machine​

A model of agent behavior showing states (MONITOR, ANALYZE, etc.) and transitions between them.

Workload Identity​

Cryptographic identity for software services. Each agent has an SVID proving who they are.

Building Systems​

HVAC​

Heating, Ventilation, and Air Conditioning system. Controls building temperature and air quality.

BMS (Building Management System)​

Software that controls building systems (HVAC, lighting, access control). Examples: Schneider EcoStruxure, Johnson Controls.

Access Control​

System managing who can enter which areas. Includes badge readers, door locks, visitor management.

Demand Response (DR)​

Utility program paying buildings to reduce electricity during peak times. Energy Agent can participate automatically.

Time-of-Use (TOU) Rates​

Electricity pricing that varies by time of day. Peak hours cost more than off-peak.

Safety & Security​

Fail-Safe Default​

When something goes wrong or is uncertain, default to the safe option. Example: If policy check fails, deny the action.

Audit Trail​

Complete log of all agent actions. Required for compliance, debugging, and accountability.

Policy Violation​

When an agent attempts an action that breaks a policy rule. Action is denied and logged.

Threat Score​

Numerical rating (0-100) of security threat severity. Calculated by Security Agent based on multiple factors.

Integration Terms​

MCP Adapter​

Software component that translates between MCP standard and vendor-specific APIs. Allows CitadelMesh to work with any vendor.

Tool Server​

MCP service that provides tools (actions) agents can invoke. Example: "lock_door" tool from Schneider adapter.

Vendor-Neutral​

Not locked into one manufacturer. Works with equipment from Schneider, Avigilon, Honeywell, Siemens, etc.

Events & Communication​

CloudEvent​

Standardized event format with type, source, ID, timestamp, and data payload.

Event Bus​

Message broker (NATS) that routes events from publishers to subscribers.

Pub/Sub (Publish-Subscribe)​

Communication pattern where publishers send events to topics, subscribers receive events they're interested in.

Correlation ID​

Unique identifier linking related events across multiple services. Enables distributed tracing.

Observability​

OpenTelemetry​

Standard for collecting metrics, traces, and logs from distributed systems.

Distributed Tracing​

Following a request across multiple services. Shows how Security Agent → OPA → MCP Adapter flows.

Metrics​

Numerical measurements over time. Example: agent response time, energy consumption, threat detection count.

Structured Logging​

Log messages in JSON format with consistent fields. Makes logs searchable and analyzable.

Development​

.NET Aspire​

Microsoft development stack for orchestrating microservices locally. Provides dashboard, hot reload, service discovery.

Hot Reload​

Updating code while services run, no restart needed. Speeds up development iteration.

Protobuf (Protocol Buffers)​

Google's data serialization format. Type-safe, compact, fast. Used for all CitadelMesh events.

gRPC​

Google's RPC framework using Protobuf. Efficient communication between services.

Agent Behavior​

Perceive​

Agent gathers information from environment (sensors, cameras, meters).

Reason​

Agent analyzes information and decides what action to take.

Act​

Agent executes decision (lock door, adjust HVAC, send alert).

Learn​

Agent improves behavior based on past results.

State Transition​

Moving from one state to another in state machine. Example: MONITOR → ANALYZE when threat detected.

Coordination​

Conflict Resolution​

When two agents want contradictory things, orchestrator decides which takes priority.

Priority Hierarchy​

Life Safety (100) > Security (80) > Comfort (50) > Cost (30). Higher number wins conflicts.

Resource Allocation​

Assigning shared resources (doors, HVAC zones) to agents that need them.

Escalation​

When orchestrator can't resolve conflict automatically, it asks humans for guidance.

Performance​

Latency​

Time from event detection to action execution. Target: under 200ms for security responses.

Throughput​

Number of events processed per second. Target: 30+ events/second.

Response Time​

How long agent takes to analyze and decide. Measured in milliseconds.

Deployment​

K3s​

Lightweight Kubernetes for edge deployment. Runs CitadelMesh at the building.

Container​

Packaged software with all dependencies. Docker/Podman format.

Service Mesh​

Network infrastructure connecting microservices. Handles routing, security, observability.

Quick Reference​

TermShort Definition
AgentSoftware that perceives, reasons, acts, learns
OPAPolicy engine validating agent actions
MCPStandard vendor integration interface
SPIFFEZero-trust identity for services
CloudEventsStandard event format
Edge-FirstRunning at building, not cloud
OrchestratorCoordinates multiple agents
Demand ResponseUtility paying to reduce power
Fail-SafeDefault to safe option when uncertain
Distributed TracingFollowing requests across services

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