¶ Layers of Interoperability
In the eTag Fuse platform, the Layers of Interoperability define how execution happens across systems, humans, and AI assistants — with explainability, policy enforcement, and lifecycle-governed knowledge.
Fuse’s layered model combines integration, automation, orchestration, and interoperability into a composable, governed execution stack. At the foundation of this model is the Knowledge Layer (Layer Zero) — a trust-scored, lifecycle-managed, and ambient infrastructure that enables all other layers.
Terminology Note
Throughout this documentation, these are referred to as both execution layers and the Layers of Interoperability.
- The execution layers define how behavior is triggered, automated, coordinated, and validated inside Fuse.
- The Layers of Interoperability refer to the overall model — ensuring trusted, explainable, policy-enforced collaboration across domains, systems, AI operators, and humans.
Execution is the mechanism. Interoperability is the outcome.
¶ 
Knowledge Layer (Zero)
“Knowledge is not an execution layer — it is what makes execution explainable, governed, and reusable.”
¶ 
What it governs
Curated, versioned knowledge artifacts
Prompt context for AI operators and models
Explainability and provenance for every decision
Lifecycle and trust enforcement for runtime access
Semantic search, injection, and filtering
¶ 
What it enables
- AI-safe knowledge reuse with prompt injection
- Cross-domain policy validation
- Auditable runtime reasoning
- Dynamic context enrichment across all layers
- Trust-scored orchestration inputs
¶ 
Key Principle
Ambient, not executed — the Knowledge Layer doesn’t run logic, but makes execution trustworthy, explainable, and governed.
See also:
¶ 
Integration Layer (1)
“Integration governs how trusted data and identity enter the platform.”
¶ What it governs
- Connection to external systems, APIs, and data streams
- Edge identity, token handling, and access validation
- Format transformation (JSON, XML, EDI, CSV, etc.)
- Real-time and batch communication pipelines
¶ What it enables
- System-to-system handoff with structured identity
- Knowledge ingestion (documents, APIs, files)
- Runtime triggers based on external events
- Secure onboarding of external records and context
¶ Key Principle
Connective, not intelligent — it moves and secures data, but doesn’t interpret or decide on it.
Related:
Routing Domain
Storage Domain
¶ 
Automation Layer (2)
“Automation responds to events — Knowledge tells it what matters.”
¶ What it governs
- Event-driven triggers, timers, and logic blocks
- Execution of actions in response to system or user events
- Reusable rules across workflows or domains
- Invocation of AI models or assistant actions
¶ What it enables
- Scalable, composable automation logic
- AI-enhanced actions (e.g., summarizing, tagging, routing)
- Rule-based logic governed by trust-scored knowledge
- Reuse of automation across workflows
¶ Key Principle
Reactive, not contextual — automation fires based on rules, but relies on Knowledge to explain, scope, or trace decisions.
Related:
¶ Orchestration Layer (3)
“Orchestration coordinates trust-aligned execution across humans, AI, and systems.”
¶ What it governs
- Multi-step workflow execution
- Human-AI coordination with approval and retry logic
- Cross-domain task flows with token inheritance
- Runtime usage of structured knowledge for task routing
¶ What it enables
- Scoped knowledge injection into decisions and reviews
- Human-in-the-loop prompts and escalation paths
- Stateful orchestration with fallback and compensation
- Domain-aware execution logic with traceable context
¶ Key Principle
Coordinated, not isolated — orchestrates logic across domains with identity, approvals, and trusted context.
Related:
¶ 
Interoperability Layer (X)
“Interoperability is not a function — it’s a compositional outcome. That’s why it’s called the X Layer.”
The Interoperability Layer is often referred to as the “X Layer” within Fuse.
- “X” represents cross-domain execution
- “X” captures the intersection of systems, actors, and AI
- “X” reflects the executed outcome of governed behavior
Fuse treats the X Layer not as something invoked, but something achieved when all upstream layers — and knowledge — align.
¶ What it governs
- Enforcement of runtime policies across domains
- Composition validation of all other execution layers
- Token resolution and domain-scoped governance
- Trust-qualified behavior for AI assistants and systems
¶ What it enables
- Cross-domain policy alignment and traceable execution
- Runtime validation that workflows are compliant
- Secure AI actioning based on verified context
- Multi-system collaboration with token-scoped trust
¶ Key Principle
Executed, not ambient — the X Layer validates governed success across domains, not just runtime flow.
Related:
¶ 
Execution Framework Diagram
This diagram reflects how Interoperability — the X Layer — emerges from the coordinated execution of Integration, Automation, and Orchestration, while Knowledge surrounds all execution as a trust-scored infrastructure.
¶ 
Summary of Execution Layers
| Layer | Name | Behavior Summary |
|---|---|---|
| Zero | Knowledge |
Ambient, structured, trust-scored knowledge that powers every other layer |
| 1 | Integration |
Securely connects systems and normalizes data at the entry point |
| 2 | Automation |
Executes rule-based or AI-enhanced logic in response to triggers |
| 3 | Orchestration |
Coordinates humans, AI, workflows, and approvals with scoped policies |
| X | Interoperability |
Ensures explainable, cross-domain, policy-aligned execution |
¶ 
Why These Layers Matter
- Execution is not just a flow — it is governed knowledge in motion
- AI operator act with scoped, explainable prompts
- Every action is traceable to structured, reviewed knowledge
- Policy and trust gates are enforced in real time
- Fuse turns interoperability into an executed, explainable outcome
¶ 
Related Pages
- Knowledge Layer — Explains how ambient, trust-scored knowledge enables all other execution layers.
- Integration Layer — Describes how external systems connect, normalize, and enforce edge governance.
- Automation Layer — Details how trigger-based logic and AI-enhanced actions are executed across domains.
- Orchestration Layer — Covers how workflows, retries, approvals, and human-AI interactions are coordinated.
- Interoperability Layer — Defines the X Layer: the executed outcome of governed, cross-domain behavior.
- Knowledge as Infrastructure — Introduces the strategic model for governing and operationalizing knowledge across the enterprise.
- Knowledge Lifecycle Governance — Defines how knowledge is versioned, reviewed, trust-scored, and eligible for execution.
Knowledge Domain — Explains how resources, embeddings, and prompts are structured and retrieved at runtime.
Next: Knowledge Layer — Learn how trust-scored, structured knowledge empowers every other layer in Fuse.
Ownership, Review, Status, and System Instructions
¶ Ownership
- Owner: Platform Architecture Team
- Contributors: Knowledge Infrastructure Team, Interoperability Governance Group
- Reviewer: Director of AI Integration
- Approver: Chief Platform Architect
¶ Review
- Last Reviewed: 2025-05-22
- Next Review Due: 2026-05-22
¶ System Instructions
systemInstructions:
purpose: "Defines the five execution layers in the Fuse platform, with a focus on how the Knowledge Layer (Layer Zero) enables explainable, policy-aligned behavior across Integration, Automation, Orchestration, and the X Layer (Interoperability)."
llmGuidance: "Use this page to explain how execution flows in Fuse. Distinguish between ambient knowledge (Layer 0) and composable execution logic (Layers 1–3). The X Layer (Layer 4) is the outcome when governed execution succeeds. Use this to guide how AI, humans, and systems interoperate with traceability and trust."
trustLevel: High
knowledgeType: ExecutionFramework