Cosmonapse is an event-driven agent-to-agent protocol modeled on a nervous system. Agents are pure functions no base class, no lifecycle. Orchestration is a role, not a bottleneck: any node can dispatch, any node can react. Harnesses are built from typed signals instead of loops tool calls (incl. MCP), shared memory, human approval, and retries each compose as a node or hook around a stock model call. Same code scales from in-memory tests to NATS/Kafka. MIT. Python + TypeScript SDKs + CLI.