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Node reference

An agent is a graph of nodes wired together by edges. Each node does one job — take an input, call a model, run a tool, choose a branch — and passes its result to the next. This page is the map: every node type, what it does, and where to read the details.

If you are new to graphs, start with Nodes, ports and edges for the underlying model, then come back here to look up a specific node. The editor tour shows where these nodes live on screen.

The palette, grouped by kind

Every node has a kind — one of three fixed categories that decide how it behaves and where it sits in the editor's left-hand palette:

Kind Palette group What these nodes do
boundary I/O & Human Enter, leave, or pause the graph.
activity Compute & Tools Do real work with side effects — call a model, a tool, an engine.
orchestration Control flow Steer the run deterministically — branch, reshape, gate.

The palette derives its list directly from the set of runnable node types, so the tables below are exhaustive. Search and category chips at the top of the palette filter it; groups are collapsible.

I/O & Human (boundary)

Type Purpose Reference
input The agent's entry point — carries the run input into the graph. Input & output
output The agent's exit — the value that reaches it becomes the run result. Input & output
human Pauses the run for a person to supply input or approve. Durable-only. Human approval
subgraph Runs another saved agent as a single step. Durable-only. Subgraph, loop & map

Compute & Tools (activity)

Type Purpose Reference
llm Calls a language model with templated messages; optional tool-calling and streaming. LLM
tool Runs a built-in tool or an HTTP API — as a pipeline step or a model capability. Tools
mcp_tool Calls a tool exposed by a connected MCP server. MCP tools
transcribe Speech-to-text: turns audio into text. Audio & images
speak Text-to-speech: turns text into audio. Audio & images
imagine Generates an image from a text prompt. Audio & images
ratelimit Allows or denies a request by a request-count limit per key per window. Rate limit & quota
quota Allows or denies a request by a token budget per key per window. Rate limit & quota

The Tool node has three kinds

mcp_tool is not dragged from the palette — it is the MCP kind of the one Tool node, chosen in the inspector after you drop a Tool. The other two kinds are a built-in tool and an HTTP call. See Tools and MCP tools.

Control flow (orchestration)

Type Purpose Reference
router Sends the run down exactly one named branch, chosen at runtime. Router
transform Reshapes a value with a deterministic template — no model, no I/O. Transform
guardrail Checks a value and routes it to a pass or block port. Guardrail
loop Runs a saved agent repeatedly, feeding each output into the next. Durable-only. Subgraph, loop & map
map Runs a saved agent once per list element, optionally in parallel. Durable-only. Subgraph, loop & map

The guardrail exception

A guardrail's kind depends on how you configure it: an inline rule check is orchestration, while a model-judge check is an activity (it makes a real model call). The editor sets the right kind for you — you never touch it. In the palette it lives under Control flow. See Guardrail.

Durable-only nodes

Four node types run only on the durable runtime, because they wait, recurse, or fan out over time: human, subgraph, loop, and map. A graph that contains any of them cannot run on the plain interactive path — save it, then use Run durably (or deploy it behind a trigger). The editor marks these nodes with a "Durable-only" banner. See Durable runs.

Reading a node on the canvas

Each node card shows an icon, a label (falling back to the node id), and its type in small caps. A colored dot and border encode the kind: green for boundary, blue for activity, amber for orchestration.

Nodes connect through handles on their edges:

  • Data handles are round, on the left (in) and right (out) sides. A required in-port handle is blue; an optional one is gray. An error out-port (err) is red.
  • Control handles are amber squares on the top and bottom — pure sequencing ("run after this"), carrying no value.
  • Tool handles are violet squares — they wire a tool node's capability into a model. See LLM.

You can only connect like to like (data to data, control to control, tool to tool). More on this in The editor.

What isn't here

A handful of type ids exist in the underlying schema but do not run yet and never appear in the palette: agent, rag, retriever, memory, code, condition, and iterator. If you hand-write raw IR that uses one, the control plane refuses to run it. Build with the runnable types above.