n8n 101
OpenBox plugs into n8n through OpenBox: Agent, a community node that ports the same governance middleware used by the OpenBox LangChain SDK directly into n8n's node runtime. This page covers the n8n concepts you will see in the OpenBox docs and shows how each one maps to governance and telemetry.
Concepts At A Glance
Agent
In n8n, an agent is an AI Agent–style node that coordinates model reasoning and tool execution: it takes a prompt, calls a connected Chat Model, decides whether to call a Tool, and loops until it has a final response.
OpenBox connection: The OpenBox: Agent node is a drop-in replacement for n8n's standard AI Agent node. Each node execution becomes a run-like session in OpenBox. The node emits lifecycle events for that run and associates model and tool events with it.
Model Call
A model call is the request the agent node sends to whatever Chat Model sub-node is connected to it — OpenAI Chat Model, Anthropic Chat Model, and others.
OpenBox connection: Model calls are governed through LLMStarted and
LLMCompleted events. OpenBox can evaluate the prompt before the model runs
and the response after the model returns.
Tool
A tool is a Tool sub-node connected to the agent's Tool input — an HTTP Request Tool, Code Tool, Vector Store Tool, or any other callable capability the agent can invoke.
OpenBox connection: Tools are governed through ToolStarted and
ToolCompleted events. These are the main boundaries for live approvals,
input/output guardrails, and tool health metrics.
Middleware
In LangChain's Python runtime, middleware wraps the agent lifecycle, model calls, and tool calls. n8n has no equivalent middleware hook API for nodes.
OpenBox connection: instead of an injected middleware object, the same governance logic ships built directly into the OpenBox: Agent node — a 1:1 TypeScript port of the LangChain middleware. The node's execution function is the integration point: it sends governed events and telemetry to OpenBox, receives verdicts, and enforces those verdicts at runtime.
Where OpenBox Sits In The Flow
- Your workflow trigger runs the OpenBox: Agent node.
- The node intercepts the agent, model, and tool boundaries as it runs its loop.
- OpenBox evaluates policy, approvals, and guardrails, then returns a verdict.
- Execution continues, waits for approval, or stops based on that verdict.
Why This Matters In The UI
These runtime distinctions explain common operator questions:
- Model calls show up as LLM lifecycle events tied to the connected Chat Model sub-node.
- Tool calls show up as governed tool events, one per connected Tool sub-node invocation.
- The user prompt — from a Chat Trigger or the node's Prompt field — is captured as signal-style context.
- Tool health is visible only for agents that actually have Tool sub-nodes connected and invoked.
- Token usage appears when the connected Chat Model returns usage metadata.