Protocol Architecture
MPLP defines a strict four-layer architecture (L1–L4) that separates protocol semantics, coordination, execution, and integration concerns, ensuring long-term stability and vendor neutrality.
Protocol Topology
The 4-Layer Model
A layered separation of protocol semantics, governance, execution, and integration.
Core Protocol
Semantic Foundation (Normative)
Defines stable protocol semantics and canonical data structures. L1 is the normative foundation of MPLP (schemas, invariants, and lifecycle primitives) and is independent of any execution environment.
Versioned & Governed · RFC Required
Coordination
Rules Layer (Normative)
Defines coordination and governance semantics for multi-agent execution. L2 constrains how agents collaborate, confirm actions, record structured traces, and comply with protocol-level duties.
Composable Modules · Duty Enforced
Execution Runtime
Behavioral Layer (Non-Prescriptive)
Defines how MPLP semantics are realized during execution. L3 covers runtime concerns such as AEL loops, VSL logic, and the Project Semantic Graph (PSG) to keep long-running behavior governable and replayable.
Implementation Agnostic · Contract Driven
Integration Layer
Boundary Layer (Optional)
Defines integration boundaries between MPLP and external systems (models, tools, APIs, infrastructure). L4 ensures integrations do not leak external concerns into the core protocol, and remain governed objects.
External Boundaries · Governed I/O
Cross-Cutting
Cross-Cutting Duties
Protocol-level responsibilities that apply across L1–L3 (and constrain L4 integrations), ensuring observability, safety, and consistency throughout the execution lifecycle.