Introduction
What OpenBook is, who it's for, and what makes its workflow engine different.
OpenBook is an open-source, self-hostable platform for building, running, and orchestrating AI agents and workflows. It combines a visual, drag-and-drop workflow canvas with a genuinely agentic runtime: agents call their own tools mid-run while the engine orchestrates branching, error handling, variables, and human approvals around them.
OpenBook is MIT-licensed. Run it on your own infrastructure, bring your own model keys, and extend it with plugins. There is no required cloud and no per-run pricing.
What you can build
- Scheduled digests — fetch from RSS/Reddit/HN, score and rank with an agent, email a formatted digest.
- Support agents — a customer message triggers a workflow that looks up an order over HTTP, branches on the situation, and routes risky actions to a human for approval.
- Multi-agent pipelines — a chain of specialist agents that hand structured work to each other.
- Event-driven automations — fire a workflow from a webhook or a named domain event like
order.updated.
Why the engine is different
Most "AI workflow" tools can draw a graph but can't actually branch, can't recover from a failed step, and can't pause for a human. OpenBook's executor does all three — and treats agents, memory, and plugins as first-class.
| Capability | What it means |
|---|---|
| Conditional branching | condition nodes route the true/false branch and prune the other — not every node fires. |
| Error paths | A node that throws routes to an error branch instead of failing the whole run. |
| Variables | set_variable writes a workflow-scoped bag; read ${vars.x} anywhere downstream. |
| Human-in-the-loop | human.handoff pauses the run and resumes on approval / input / choice. |
| Core memory | Every agent gets long-term memory by default — no plugin to install. |
| AI builder | Describe a workflow in English; it creates the agents and wires the graph. |
Next steps
- Quickstart — clone, run, and fire your first workflow.
- Core concepts — agents, actions, workflows, memory, plugins.
- The workflow engine — nodes, data flow, and interpolation.