Orchestrator Canvas
User Manual

End-user and developer guide for WORMWOOD_APP.html — the Nexus visual pipeline builder. Covers connecting to the engine, building pipeline graphs, configuring nodes, saving and running pipelines, canvas navigation, demo mode, themes, and URL parameters.

The Orchestrator Canvas is the pipeline designer inside Nexus. It lets you visually build, edit, and run process pipelines as directed acyclic graphs (DAGs). Each pipeline node represents a single processing step; edges represent data flow between steps.

The canvas operates at Level 1 (Macro scale) of the Nexus 4-resolution model — the highest level, where entire workflow graphs are composed and executed.

Direct URL

The canvas is served by the Wormwood engine at:

http://localhost:8011/nexus-ui/WORMWOOD_APP.html

Append URL parameters to pre-configure the session (see Section 12).

From the Hub Dashboard

1. Log in to NEXUS_APP.html
2. From the hub, click the "ORCHESTRATOR" button in the top bar, or use the FAB → Orchestrator
3. The canvas opens in a new tab pre-loaded with the current app and skin

Connecting to the Engine

On first load, the canvas reads the ?key= URL parameter for your API key. If absent, it tries a stored key from localStorage. Without a valid key, all API calls return 401 and the SSE indicator shows OFFLINE.

1. In the top bar, open the App selector dropdown and choose the app you want to work with
2. The Pipeline selector populates with all pipelines belonging to that app
3. Select a pipeline from the dropdown
4. The canvas clears and loads the pipeline graph — nodes and edges appear
5. The breadcrumb bar below the topbar updates to show the loaded pipeline name

Empty Canvas

If no pipeline is selected, the canvas is blank. This is the correct initial state. Select a pipeline or create a new one before editing.

Pan

Hold Space and drag anywhere on the canvas background, or right-click-drag. The cursor changes to a grab hand during pan.

Zoom

Keyboard Shortcuts

Adding a Node

1. Click PALETTE in the toolbar to open the node type panel on the right
2. Find the node type you want (node types are grouped by category)
3. Drag the node from the palette onto the canvas at the desired position
4. The node appears with its default name and two connection pins (input and output)

Node Categories

Moving a Node

Click and hold on a node body (not a pin) and drag to reposition it. Edges connected to the node follow the node in real time.

Selecting a Node

Click once on a node to select it. The selected node renders with an accent outline. The DELETE button in the toolbar becomes active.

Deleting a Node

1. Click the node to select it
2. Press Delete or click the DELETE toolbar button
3. The node and all its connected edges are removed from the canvas

Each node has small circular pins on its left (input) and right (output) sides.

1. Hover over a node's output pin (right circle) — the cursor changes
2. Click and drag from the output pin towards the target node
3. A dashed temporary edge follows your cursor
4. Release the mouse over the input pin (left circle) of the target node
5. The edge is created and renders as a bezier curve between the two nodes

Deleting an Edge

Edges cannot currently be deleted individually from the canvas. To remove a connection, reconfigure the pipeline by deleting the relevant node and re-adding it, or edit the graph JSON directly via the engine API (PUT /pipelines/{id}).

Opening the Config Panel

Double-click any node on the canvas. The Class Panel slides in from the right, showing the node's configuration fields.

Panel Sections

Editing Properties

1. Double-click the node to open the Class Panel
2. Click the property value field you want to change — it becomes editable (contenteditable)
3. Type the new value
4. Click outside the field or press Enter to confirm
5. Changes are stored in memory; click SAVE to persist to the engine

Inline Rule Editor (Pico Scale)

Click EDIT RULE in the Rule Reference section to open the Pico-scale rule editor directly inside the panel. This editor lets you write or modify the Lua rule expression that governs the node's execution logic.

1. Ensure a pipeline is selected in the Pipeline selector
2. Click SAVE in the top bar
3. The status bar at the bottom shows Saved: [pipeline name] v[version] on success

1. Select the pipeline you want to run from the Pipeline selector
2. Click RUN in the top bar
3. The Run Log panel opens on the right, showing execution events in real time via SSE
4. Node status indicators on the canvas update as each node executes (pending → running → pass/fail)
5. When execution completes, the final status is shown in the run log

Run Log Panel

The run log panel shows a live stream of pipeline events. Each line contains a timestamp, node name, event type, and message. Errors appear in red. Warnings in amber. Successful node completions in green.

Demo mode is available for specific pipelines that have a defined demo sequence (e.g., nesto-worker-onboard-full). When such a pipeline is loaded, the DEMO button appears in the top bar.

1. Load a demo-enabled pipeline
2. The DEMO button becomes visible in the right side of the top bar
3. Click DEMO to start the autonomous demo sequence
4. The canvas animates through each node in sequence, highlighting execution flow with timed transitions
5. Demo completes automatically; a completion message appears in the status log

Example Full URL

http://localhost:8011/nexus-ui/WORMWOOD_APP.html?org=arc&pipeline=nesto-worker-onboard-full&skin=glass-ember&key=local-test-key

This URL opens the canvas, applies the glass-ember skin, selects the ARC app, and loads the Nesto Worker Onboard pipeline immediately — ready to edit or demo without any manual selection.

Skin preferences are stored in localStorage under the key nexus-theme. The stored skin applies automatically on next load even without the URL parameter.

The level tabs in the topbar switch the canvas between the four Nexus resolution levels. Each level holds an independent graph.

1. Select an app from the App selector (the pipeline must belong to an app)
2. Click NEW PIPELINE in the top bar
3. Enter a name for the new pipeline in the prompt
4. An empty pipeline is created in the engine and selected in the Pipeline selector
5. The canvas clears — you are now editing the new empty pipeline
6. Add nodes from the palette, connect them, configure each node, then click SAVE

The SSE (Server-Sent Events) indicator in the toolbar shows the live connection to the engine: