Multi-Agent Handoff & State Protocol Engine

The Multi-Agent Handoff & State Protocol Engine is an architectural standard and runtime state synchronization framework designed to eliminate context loss, task duplication, and conversation window bloat across multi-agent workflows (LangGraph, CrewAI, AutoGen, OpenAI Swarm, Claude Code subagents).

When autonomous agents pass tasks to downstream agents using raw conversational histories, downstream agents lose critical context, repeat completed steps, or hallucinate task boundaries. This protocol establishes immutable, schema-validated state transition packets ($s_t \rightarrow s_{t+1}$).

Rather than forwarding 50 turns of conversational history, the Manager agent serializes task state into an atomic, typed payload:

Downstream worker agents operate in an isolated sub-context:

1. Fresh Context Window: The worker starts with a 100% clean context window, receiving only its specific task packet and system prompt.
2. Deterministic Return Contract: When work is completed, the worker emits an evidence payload with verified output artifacts and status flags.
3. Manager State Folding: The Manager folds the worker's concise completion card into global state without absorbing intermediate verbose scratchpads.