Nodes
Overview of all node types in the Linea workflow engine.
Nodes
Every workflow is a directed graph of nodes connected by edges. Each node type serves a specific purpose — running LLM inference, branching on a condition, sending a Slack message, and so on.
For the full configuration reference for each node type, see the Node Reference section.
Variable Substitution
All string fields in node configuration support {{variableName}} substitution:
| Syntax | Resolves to |
|---|---|
{{input.field}} | Field from the trigger input payload |
{{nodeName}} | Output of a previous node (by name or ID) |
{{lastOutput}} | Output of the most recently completed node |
{{nodeResults.nodeId.output}} | Deep-access a specific node result |
{{variables.myVar}} | Any variable set during the current execution |
Substitution is applied to all string fields across all node types, including object values (e.g. individual header values in the HTTP node).
References like {{input.data.items.0.name}} with dot-path traversal work as expected. Undefined references resolve to an empty string.
Node Quick Reference
| Node | Category | Purpose |
|---|---|---|
| start | Core | Entry point — initializes state from trigger input |
| end | Core | Terminal — marks execution complete |
| agent | AI | LLM with tool use, structured output, long-term memory |
| memory | AI | Read/clear in-workflow key-value memory |
| if-else | Logic | Branch on a boolean Jexl expression |
| router | Logic | Multi-branch routing via prioritized conditions |
| http | Tools | HTTP requests to external APIs |
| mcp | Tools | Model Context Protocol tool invocation |
| transform | Data | Reshape variables with a Jexl expression |
| extract | Data | Web scraping via Firecrawl or native fetch |
| retriever | Data | Knowledge base search |
| code | Data | Sandboxed JS execution (disabled — see page) |
| loop | Flow | Iterate over an array |
| subworkflow | Flow | Call another workflow synchronously |
| guardrails | Safety | PII / jailbreak / harmful content detection |
| approval-gate | Safety | Human-in-the-loop checkpoint |
| slack | Integration | Send Slack messages or DMs |
| github | Integration | GitHub issues and pull requests |
| notion | Integration | Notion pages and database queries |
| gmail | Integration | Send and read Gmail messages |
| note | Misc | Canvas annotation (no runtime effect) |