refactoring

frontend/docs/IMPROVEMENTS.md

@@ -21,6 +21,16 @@ This doc summarizes recent improvements and suggested next steps for readability
 
 - **rendering.ts** documents the 3-step pipeline, how to add a source/output type, and points to `templateRefs.ts` for shared helpers.
 
+### 4. Rendering signatures (pure module)
+
+- **Added** `lib/graph/renderingSignatures.ts`: `buildConnectedNodeIds`, `buildSourceSignatures` (connectedNodeIds + all five signatures + sourceSignature).
+- **Refactored** `useRenderingNodeState` to call `buildSourceSignatures` in a single useMemo; hook is shorter and signature logic is testable in isolation.
+
+### 5. Canvas split
+
+- **CanvasContextMenuContent** (`app/canvas/CanvasContextMenuContent.tsx`): context menu content (Create Node grouped by classification, Paste). CanvasPage passes `onCreateNode` and `onPaste`.
+- **useCanvasConnectionPath** (`app/canvas/useCanvasConnectionPath.ts`): all connection-path state and callbacks (updating/trigger/paused/error node ids, path node ids, start/end update, add/remove paused/error). CanvasPage calls the hook with `edges` and passes the result into FlowContext.
+
 ## Design patterns in use
 
 | Pattern        | Where                                      |
@@ -33,15 +43,8 @@ This doc summarizes recent improvements and suggested next steps for readability
 
 ## Suggested next steps
 
-1. **CanvasPage** (~950 lines): Split into smaller units, e.g.:
-   - `useCanvasGraph()` or similar for graph state and connection rules.
-   - A dedicated component for the context menu (add node, paste, etc.).
-   - Keeps CanvasPage as composition + layout.
+1. **CanvasPage**: Further split optional: e.g. `useCanvasGraph()` for graph state + persistence + connection rules, so the page is mostly composition and layout.
 
-2. **useRenderingNodeState**: Consider extracting:
-   - Signature building (config/edges/variables/functions/data) into a pure function or small module, e.g. `buildSourceSignatures(nodes, edges, id, incomingIds, getConfigContent)`.
-   - Makes the hook easier to read and the logic testable in isolation.
+2. **Config types**: If you add more output types (e.g. Mermaid), consider a small registry API (`registerConfigType`, `getConfigType`) instead of a single large `CONFIG_TYPES` array.
 
-3. **Config types**: If you add more output types (e.g. Mermaid), consider a small registry API (`registerConfigType`, `getConfigType`) instead of a single large `CONFIG_TYPES` array, so extensions can register without editing the core list.
-
-4. **Consistent node shape in lib**: `templateRefs` uses `EdgeLike` / `NodeLike`; other graph code uses inline `{ source, target }` or `nodes as ...`. You could standardize on the same minimal types where appropriate to reduce casts.
+3. **Consistent node shape in lib**: `templateRefs` and `renderingSignatures` use `EdgeLike` / `NodeLike`; standardize where appropriate to reduce casts.

frontend/src/app/canvas/CanvasContextMenuContent.tsx

@@ -0,0 +1,62 @@
+/**
+ * Context menu content for the canvas: Create Node (grouped by classification) and Paste.
+ * Used inside CanvasPage so the menu structure lives in one place.
+ */
+
+import React from 'react'
+import {
+  ContextMenuContent,
+  ContextMenuItem,
+  ContextMenuGroup,
+  ContextMenuLabel,
+  ContextMenuSeparator,
+  ContextMenuSub,
+  ContextMenuSubContent,
+  ContextMenuSubTrigger,
+} from '@/components/ui/context-menu'
+import { ClipboardPaste } from 'lucide-react'
+import { getRegisteredNodeTypesGroupedByClassification } from '@/lib/graph/nodeRegistry'
+
+export type CanvasContextMenuContentProps = {
+  onCreateNode: (type: string) => void
+  onPaste: () => void
+}
+
+export function CanvasContextMenuContent({ onCreateNode, onPaste }: CanvasContextMenuContentProps) {
+  const groups = getRegisteredNodeTypesGroupedByClassification()
+  return (
+    <ContextMenuContent className="w-48" aria-label="Canvas menu: create node or paste">
+      <ContextMenuGroup>
+        <ContextMenuSub>
+          <ContextMenuSubTrigger>Create Node</ContextMenuSubTrigger>
+          <ContextMenuSubContent className="w-44">
+            {groups.map(
+              (group, groupIndex) =>
+                group.types.length > 0 && (
+                  <React.Fragment key={group.classification}>
+                    {groupIndex > 0 && <ContextMenuSeparator />}
+                    <ContextMenuGroup>
+                      <ContextMenuLabel className="text-muted-foreground">
+                        {group.label}
+                      </ContextMenuLabel>
+                      {group.types.map((desc) => (
+                        <ContextMenuItem key={desc.id} onSelect={() => onCreateNode(desc.id)}>
+                          {desc.menuIcon}
+                          {desc.menuLabel}
+                        </ContextMenuItem>
+                      ))}
+                    </ContextMenuGroup>
+                  </React.Fragment>
+                )
+            )}
+          </ContextMenuSubContent>
+        </ContextMenuSub>
+        <ContextMenuSeparator />
+        <ContextMenuItem onSelect={onPaste}>
+          <ClipboardPaste className="mr-2 h-4 w-4" />
+          Paste
+        </ContextMenuItem>
+      </ContextMenuGroup>
+    </ContextMenuContent>
+  )
+}

frontend/src/app/canvas/CanvasPage.tsx

@@ -27,18 +27,9 @@ import FlowContext from '@/lib/graph/flowContext'
 import { useTheme } from '@/lib/themeContext'
 import { usePlatform } from '@/app/kosmos/KosmosContext'
 import { useGraphStateWithHistory } from '@/hooks/useGraphStateWithHistory'
-import {
-  ContextMenu,
-  ContextMenuContent,
-  ContextMenuItem,
-  ContextMenuLabel,
-  ContextMenuSeparator,
-  ContextMenuSub,
-  ContextMenuSubContent,
-  ContextMenuSubTrigger,
-  ContextMenuTrigger,
-  ContextMenuGroup,
-} from '@/components/ui/context-menu'
+import { ContextMenu, ContextMenuTrigger } from '@/components/ui/context-menu'
+import { CanvasContextMenuContent } from '@/app/canvas/CanvasContextMenuContent'
+import { useCanvasConnectionPath } from '@/app/canvas/useCanvasConnectionPath'
 import { CanvasMenubar } from '@/app/canvas/CanvasMenubar'
 import { createContextualNode } from '@/app/canvas/ContextualZoomNode'
 import { FlowKeyboardShortcuts } from '@/components/graph/FlowKeyboardShortcuts'
@@ -56,17 +47,15 @@ import {
   DialogContent,
   DialogTitle,
 } from '@/components/ui/dialog'
-import { ClipboardPaste, FolderOpen, FileStack, CircleDotDashed } from 'lucide-react'
+import { FolderOpen, FileStack, CircleDotDashed } from 'lucide-react'
 import { DEFAULT_NODE_STYLE, getDefaultDataForType, getNextNodeId } from '@/lib/graph/flowUtils'
 import {
   getRegisteredNodeTypes,
-  getRegisteredNodeTypesGroupedByClassification,
   getRegisteredNodeTypeIds,
   getDefaultStyle,
   getNodeType,
   isConnectionAllowed,
 } from '@/lib/graph/nodeRegistry'
-import { getPathNodeIds, getPausedSegmentNodeIds } from '@/lib/graph/graphPath'
 import type { AppNode, AppEdge } from '@/lib/graph/nodeTypes'
 import { toast } from 'sonner'
 import {
@@ -78,8 +67,6 @@ import {
 
 const SNAP_GRID: [number, number] = [15, 15]
 const DUPLICATE_OFFSET = { x: 30, y: 30 }
-/** Minimum time (ms) the connection ant trail runs when a path update is in progress. */
-const CONNECTION_PATH_UPDATE_MIN_MS = 1500
 const snapToGrid = (x: number, y: number): { x: number; y: number } => ({
   x: Math.round(x / SNAP_GRID[0]) * SNAP_GRID[0],
   y: Math.round(y / SNAP_GRID[1]) * SNAP_GRID[1],
@@ -267,82 +254,7 @@ export function CanvasPage({ projectId }: CanvasPageProps) {
   const [isSelecting, setIsSelecting] = React.useState(false)
   const [ariaAnnouncement, setAriaAnnouncement] = React.useState<string | null>(null)
   const [fullscreenNodeId, setFullscreenNodeId] = React.useState<string | null>(null)
-  const [connectionPathUpdatingNodeIds, setConnectionPathUpdatingNodeIds] = React.useState<string[]>([])
-  const [connectionPathTriggerNodeIds, setConnectionPathTriggerNodeIds] = React.useState<string[]>([])
-  const pathUpdateNodeIdsRef = useRef<Set<string>>(new Set())
-  const pathUpdateStartTimeRef = useRef<number | null>(null)
-  const pathUpdateEndTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null)
-
-  const [connectionPathPausedNodeIds, setConnectionPathPausedNodeIds] = React.useState<string[]>([])
-  const [connectionPathErrorNodeIds, setConnectionPathErrorNodeIds] = React.useState<string[]>([])
-  const connectionPathPausedNodeIdsRef = useRef<string[]>([])
-  connectionPathPausedNodeIdsRef.current = connectionPathPausedNodeIds
-
-  const clearPathUpdateSession = useCallback(() => {
-    setConnectionPathUpdatingNodeIds([])
-    if (connectionPathPausedNodeIdsRef.current.length === 0) {
-      setConnectionPathTriggerNodeIds([])
-      setConnectionPathPausedNodeIds([])
-    }
-  }, [])
-
-  const startConnectionPathUpdate = useCallback((nodeId: string) => {
-    const ref = pathUpdateNodeIdsRef.current
-    ref.add(nodeId)
-    if (ref.size === 1) {
-      pathUpdateStartTimeRef.current = Date.now()
-      if (pathUpdateEndTimeoutRef.current != null) {
-        clearTimeout(pathUpdateEndTimeoutRef.current)
-        pathUpdateEndTimeoutRef.current = null
-      }
-    }
-    setConnectionPathUpdatingNodeIds(Array.from(ref))
-  }, [])
-
-  const endConnectionPathUpdate = useCallback((nodeId: string) => {
-    const ref = pathUpdateNodeIdsRef.current
-    ref.delete(nodeId)
-    if (ref.size > 0) {
-      setConnectionPathUpdatingNodeIds(Array.from(ref))
-      return
-    }
-    const startedAt = pathUpdateStartTimeRef.current ?? 0
-    const elapsed = Date.now() - startedAt
-    const remaining = Math.max(0, CONNECTION_PATH_UPDATE_MIN_MS - elapsed)
-    if (remaining === 0) {
-      clearPathUpdateSession()
-    } else {
-      pathUpdateEndTimeoutRef.current = setTimeout(() => {
-        pathUpdateEndTimeoutRef.current = null
-        clearPathUpdateSession()
-      }, remaining)
-    }
-  }, [clearPathUpdateSession])
-
-  const pathTriggerBatchRef = useRef<Set<string>>(new Set())
-  const pathTriggerScheduledRef = useRef(false)
-  const addConnectionPathTrigger = useCallback((nodeId: string) => {
-    pathTriggerBatchRef.current.add(nodeId)
-    if (pathTriggerScheduledRef.current) return
-    pathTriggerScheduledRef.current = true
-    requestAnimationFrame(() => {
-      pathTriggerScheduledRef.current = false
-      const batch = new Set(pathTriggerBatchRef.current)
-      pathTriggerBatchRef.current = new Set()
-      if (batch.size === 0) return
-      setConnectionPathTriggerNodeIds((prev) => {
-        const next = new Set(prev)
-        batch.forEach((id) => next.add(id))
-        return next.size === prev.length && prev.every((id) => next.has(id)) ? prev : Array.from(next)
-      })
-    })
-  }, [])
-
-  React.useEffect(() => () => {
-    if (pathUpdateEndTimeoutRef.current != null) {
-      clearTimeout(pathUpdateEndTimeoutRef.current)
-    }
-  }, [])
+  const connectionPath = useCanvasConnectionPath(edges)
 
   const nodesRef = useRef(nodes)
   nodesRef.current = nodes
@@ -551,50 +463,6 @@ export function CanvasPage({ projectId }: CanvasPageProps) {
     flowActionsRef.current?.pasteAtViewportCenter?.()
   }, [])
 
-  const connectionPathNodeIds = useMemo(
-    () =>
-      getPathNodeIds(
-        edges,
-        connectionPathUpdatingNodeIds,
-        connectionPathTriggerNodeIds,
-        connectionPathPausedNodeIds
-      ),
-    [edges, connectionPathUpdatingNodeIds, connectionPathTriggerNodeIds, connectionPathPausedNodeIds]
-  )
-
-  const connectionPathPausedSegmentNodeIds = useMemo(
-    () =>
-      getPausedSegmentNodeIds(
-        edges,
-        connectionPathNodeIds,
-        connectionPathTriggerNodeIds,
-        connectionPathPausedNodeIds
-      ),
-    [edges, connectionPathNodeIds, connectionPathTriggerNodeIds, connectionPathPausedNodeIds]
-  )
-
-  const connectionPathActiveSegmentNodeIds = useMemo(() => {
-    const active = new Set(connectionPathNodeIds)
-    connectionPathPausedSegmentNodeIds.forEach((id) => active.delete(id))
-    return active
-  }, [connectionPathNodeIds, connectionPathPausedSegmentNodeIds])
-
-  const addConnectionPathPausedNode = useCallback((nodeId: string) => {
-    setConnectionPathPausedNodeIds((prev) => (prev.includes(nodeId) ? prev : [...prev, nodeId]))
-  }, [])
-
-  const removeConnectionPathPausedNode = useCallback((nodeId: string) => {
-    setConnectionPathPausedNodeIds((prev) => prev.filter((id) => id !== nodeId))
-  }, [])
-
-  const addConnectionPathError = useCallback((nodeId: string) => {
-    setConnectionPathErrorNodeIds((prev) => (prev.includes(nodeId) ? prev : [...prev, nodeId]))
-  }, [])
-
-  const removeConnectionPathError = useCallback((nodeId: string) => {
-    setConnectionPathErrorNodeIds((prev) => prev.filter((id) => id !== nodeId))
-  }, [])
-
   const flowContextValue = useMemo(
     () => ({
       nodes,
@@ -609,20 +477,20 @@ export function CanvasPage({ projectId }: CanvasPageProps) {
       flowActionsRef,
       fullscreenNodeId,
       setFullscreenNodeId,
-      connectionPathUpdatingNodeIds,
-      connectionPathTriggerNodeIds,
-      addConnectionPathTrigger,
-      connectionPathNodeIds,
-      connectionPathPausedSegmentNodeIds,
-      connectionPathActiveSegmentNodeIds,
-      connectionPathPausedNodeIds,
-      addConnectionPathPausedNode,
-      removeConnectionPathPausedNode,
-      connectionPathErrorNodeIds,
-      addConnectionPathError,
-      removeConnectionPathError,
-      startConnectionPathUpdate,
-      endConnectionPathUpdate,
+      connectionPathUpdatingNodeIds: connectionPath.connectionPathUpdatingNodeIds,
+      connectionPathTriggerNodeIds: connectionPath.connectionPathTriggerNodeIds,
+      addConnectionPathTrigger: connectionPath.addConnectionPathTrigger,
+      connectionPathNodeIds: connectionPath.connectionPathNodeIds,
+      connectionPathPausedSegmentNodeIds: connectionPath.connectionPathPausedSegmentNodeIds,
+      connectionPathActiveSegmentNodeIds: connectionPath.connectionPathActiveSegmentNodeIds,
+      connectionPathPausedNodeIds: connectionPath.connectionPathPausedNodeIds,
+      addConnectionPathPausedNode: connectionPath.addConnectionPathPausedNode,
+      removeConnectionPathPausedNode: connectionPath.removeConnectionPathPausedNode,
+      connectionPathErrorNodeIds: connectionPath.connectionPathErrorNodeIds,
+      addConnectionPathError: connectionPath.addConnectionPathError,
+      removeConnectionPathError: connectionPath.removeConnectionPathError,
+      startConnectionPathUpdate: connectionPath.startConnectionPathUpdate,
+      endConnectionPathUpdate: connectionPath.endConnectionPathUpdate,
     }),
     [
       nodes,
@@ -637,20 +505,7 @@ export function CanvasPage({ projectId }: CanvasPageProps) {
       flowActionsRef,
       fullscreenNodeId,
       setFullscreenNodeId,
-      connectionPathUpdatingNodeIds,
-      connectionPathTriggerNodeIds,
-      addConnectionPathTrigger,
-      connectionPathNodeIds,
-      connectionPathPausedSegmentNodeIds,
-      connectionPathActiveSegmentNodeIds,
-      connectionPathPausedNodeIds,
-      addConnectionPathPausedNode,
-      removeConnectionPathPausedNode,
-      connectionPathErrorNodeIds,
-      addConnectionPathError,
-      removeConnectionPathError,
-      startConnectionPathUpdate,
-      endConnectionPathUpdate,
+      connectionPath,
     ]
   )
 
@@ -900,39 +755,7 @@ export function CanvasPage({ projectId }: CanvasPageProps) {
                   </ReactFlowProvider>
                 </div>
               </ContextMenuTrigger>
-              <ContextMenuContent className="w-48" aria-label="Canvas menu: create node or paste">
-                <ContextMenuGroup>
-                  <ContextMenuSub>
-                    <ContextMenuSubTrigger>Create Node</ContextMenuSubTrigger>
-                    <ContextMenuSubContent className="w-44">
-                      {getRegisteredNodeTypesGroupedByClassification().map(
-                        (group, groupIndex) =>
-                          group.types.length > 0 && (
-                            <React.Fragment key={group.classification}>
-                              {groupIndex > 0 && <ContextMenuSeparator />}
-                              <ContextMenuGroup>
-                                <ContextMenuLabel className="text-muted-foreground">
-                                  {group.label}
-                                </ContextMenuLabel>
-                                {group.types.map((desc) => (
-                                  <ContextMenuItem key={desc.id} onSelect={() => createNode(desc.id)}>
-                                    {desc.menuIcon}
-                                    {desc.menuLabel}
-                                  </ContextMenuItem>
-                                ))}
-                              </ContextMenuGroup>
-                            </React.Fragment>
-                          )
-                      )}
-                    </ContextMenuSubContent>
-                  </ContextMenuSub>
-                  <ContextMenuSeparator />
-                  <ContextMenuItem onSelect={() => pasteNode()}>
-                    <ClipboardPaste className="mr-2 h-4 w-4" />
-                    Paste
-                  </ContextMenuItem>
-                </ContextMenuGroup>
-              </ContextMenuContent>
+              <CanvasContextMenuContent onCreateNode={createNode} onPaste={pasteNode} />
             </ContextMenu>
             {fullscreenNodeId && (
               <FullscreenNodeOverlay

frontend/src/app/canvas/useCanvasConnectionPath.ts

@@ -0,0 +1,174 @@
+/**
+ * Hook that holds all connection-path state and callbacks for the canvas.
+ * Used to show the "ant trail" along the path of an update (e.g. config → agent → render).
+ * Extracted from CanvasPage to keep the page focused on composition.
+ */
+
+import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
+import { getPathNodeIds, getPausedSegmentNodeIds } from '@/lib/graph/graphPath'
+
+export type EdgeLike = { source: string; target: string }
+
+/** Minimum time (ms) the connection ant trail runs when a path update is in progress. */
+const CONNECTION_PATH_UPDATE_MIN_MS = 1500
+
+export type UseCanvasConnectionPathResult = {
+  connectionPathUpdatingNodeIds: string[]
+  connectionPathTriggerNodeIds: string[]
+  connectionPathPausedNodeIds: string[]
+  connectionPathErrorNodeIds: string[]
+  connectionPathNodeIds: Set<string>
+  connectionPathPausedSegmentNodeIds: Set<string>
+  connectionPathActiveSegmentNodeIds: Set<string>
+  startConnectionPathUpdate: (nodeId: string) => void
+  endConnectionPathUpdate: (nodeId: string) => void
+  addConnectionPathTrigger: (nodeId: string) => void
+  addConnectionPathPausedNode: (nodeId: string) => void
+  removeConnectionPathPausedNode: (nodeId: string) => void
+  addConnectionPathError: (nodeId: string) => void
+  removeConnectionPathError: (nodeId: string) => void
+}
+
+export function useCanvasConnectionPath(edges: EdgeLike[]): UseCanvasConnectionPathResult {
+  const [connectionPathUpdatingNodeIds, setConnectionPathUpdatingNodeIds] = useState<string[]>([])
+  const [connectionPathTriggerNodeIds, setConnectionPathTriggerNodeIds] = useState<string[]>([])
+  const [connectionPathPausedNodeIds, setConnectionPathPausedNodeIds] = useState<string[]>([])
+  const [connectionPathErrorNodeIds, setConnectionPathErrorNodeIds] = useState<string[]>([])
+
+  const pathUpdateNodeIdsRef = useRef<Set<string>>(new Set())
+  const pathUpdateStartTimeRef = useRef<number | null>(null)
+  const pathUpdateEndTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null)
+  const connectionPathPausedNodeIdsRef = useRef<string[]>([])
+  connectionPathPausedNodeIdsRef.current = connectionPathPausedNodeIds
+
+  const pathTriggerBatchRef = useRef<Set<string>>(new Set())
+  const pathTriggerScheduledRef = useRef(false)
+
+  const clearPathUpdateSession = useCallback(() => {
+    setConnectionPathUpdatingNodeIds([])
+    if (connectionPathPausedNodeIdsRef.current.length === 0) {
+      setConnectionPathTriggerNodeIds([])
+      setConnectionPathPausedNodeIds([])
+    }
+  }, [])
+
+  const startConnectionPathUpdate = useCallback((nodeId: string) => {
+    const ref = pathUpdateNodeIdsRef.current
+    ref.add(nodeId)
+    if (ref.size === 1) {
+      pathUpdateStartTimeRef.current = Date.now()
+      if (pathUpdateEndTimeoutRef.current != null) {
+        clearTimeout(pathUpdateEndTimeoutRef.current)
+        pathUpdateEndTimeoutRef.current = null
+      }
+    }
+    setConnectionPathUpdatingNodeIds(Array.from(ref))
+  }, [])
+
+  const endConnectionPathUpdate = useCallback((nodeId: string) => {
+    const ref = pathUpdateNodeIdsRef.current
+    ref.delete(nodeId)
+    if (ref.size > 0) {
+      setConnectionPathUpdatingNodeIds(Array.from(ref))
+      return
+    }
+    const startedAt = pathUpdateStartTimeRef.current ?? 0
+    const elapsed = Date.now() - startedAt
+    const remaining = Math.max(0, CONNECTION_PATH_UPDATE_MIN_MS - elapsed)
+    if (remaining === 0) {
+      clearPathUpdateSession()
+    } else {
+      pathUpdateEndTimeoutRef.current = setTimeout(() => {
+        pathUpdateEndTimeoutRef.current = null
+        clearPathUpdateSession()
+      }, remaining)
+    }
+  }, [clearPathUpdateSession])
+
+  const addConnectionPathTrigger = useCallback((nodeId: string) => {
+    pathTriggerBatchRef.current.add(nodeId)
+    if (pathTriggerScheduledRef.current) return
+    pathTriggerScheduledRef.current = true
+    requestAnimationFrame(() => {
+      pathTriggerScheduledRef.current = false
+      const batch = new Set(pathTriggerBatchRef.current)
+      pathTriggerBatchRef.current = new Set()
+      if (batch.size === 0) return
+      setConnectionPathTriggerNodeIds((prev) => {
+        const next = new Set(prev)
+        batch.forEach((id) => next.add(id))
+        return next.size === prev.length && prev.every((id) => next.has(id)) ? prev : Array.from(next)
+      })
+    })
+  }, [])
+
+  useEffect(
+    () => () => {
+      if (pathUpdateEndTimeoutRef.current != null) {
+        clearTimeout(pathUpdateEndTimeoutRef.current)
+      }
+    },
+    []
+  )
+
+  const connectionPathNodeIds = useMemo(
+    () =>
+      getPathNodeIds(
+        edges,
+        connectionPathUpdatingNodeIds,
+        connectionPathTriggerNodeIds,
+        connectionPathPausedNodeIds
+      ),
+    [edges, connectionPathUpdatingNodeIds, connectionPathTriggerNodeIds, connectionPathPausedNodeIds]
+  )
+
+  const connectionPathPausedSegmentNodeIds = useMemo(
+    () =>
+      getPausedSegmentNodeIds(
+        edges,
+        connectionPathNodeIds,
+        connectionPathTriggerNodeIds,
+        connectionPathPausedNodeIds
+      ),
+    [edges, connectionPathNodeIds, connectionPathTriggerNodeIds, connectionPathPausedNodeIds]
+  )
+
+  const connectionPathActiveSegmentNodeIds = useMemo(() => {
+    const active = new Set(connectionPathNodeIds)
+    connectionPathPausedSegmentNodeIds.forEach((id) => active.delete(id))
+    return active
+  }, [connectionPathNodeIds, connectionPathPausedSegmentNodeIds])
+
+  const addConnectionPathPausedNode = useCallback((nodeId: string) => {
+    setConnectionPathPausedNodeIds((prev) => (prev.includes(nodeId) ? prev : [...prev, nodeId]))
+  }, [])
+
+  const removeConnectionPathPausedNode = useCallback((nodeId: string) => {
+    setConnectionPathPausedNodeIds((prev) => prev.filter((id) => id !== nodeId))
+  }, [])
+
+  const addConnectionPathError = useCallback((nodeId: string) => {
+    setConnectionPathErrorNodeIds((prev) => (prev.includes(nodeId) ? prev : [...prev, nodeId]))
+  }, [])
+
+  const removeConnectionPathError = useCallback((nodeId: string) => {
+    setConnectionPathErrorNodeIds((prev) => prev.filter((id) => id !== nodeId))
+  }, [])
+
+  return {
+    connectionPathUpdatingNodeIds,
+    connectionPathTriggerNodeIds,
+    connectionPathPausedNodeIds,
+    connectionPathErrorNodeIds,
+    connectionPathNodeIds,
+    connectionPathPausedSegmentNodeIds,
+    connectionPathActiveSegmentNodeIds,
+    startConnectionPathUpdate,
+    endConnectionPathUpdate,
+    addConnectionPathTrigger,
+    addConnectionPathPausedNode,
+    removeConnectionPathPausedNode,
+    addConnectionPathError,
+    removeConnectionPathError,
+  }
+}

frontend/src/components/nodes/render/useRenderingNodeState.ts

@@ -20,7 +20,7 @@ import {
     processSvgDisplay,
     stripTemplateSyntax,
 } from '@/lib/graph/rendering'
-import { isReachable, resolveExtendsRef, getTemplateRefs } from '@/lib/graph/templateRefs'
+import { buildSourceSignatures } from '@/lib/graph/renderingSignatures'
 import type { ConfigTypeId, SourceRenderingLogicContext } from '@/lib/graph/rendering'
 
 export type RenderingNodeData = {
@@ -136,101 +136,25 @@ export function useRenderingNodeState(
               ? agentOutputMarkdown
               : ''
 
-    const connectedNodeIds = useMemo(() => {
-        const edgeList = edges as { source: string; target: string }[]
-        const nodeList = nodes as { id: string; type?: string; data?: unknown }[]
-        const out = new Set<string>()
-        const addConfigRefs = (nodeId: string, visited: Set<string>) => {
-            if (visited.has(nodeId)) return
-            const node = nodeList.find((n) => n.id === nodeId && n.type === 'config')
-            if (!node) return
-            visited.add(nodeId)
-            out.add(nodeId)
-            const content = getConfigContent((node.data ?? undefined) as Record<string, unknown> | undefined)
-            for (const ref of getTemplateRefs(content)) {
-                const refId = resolveExtendsRef(nodeList, ref)
-                if (
-                    refId &&
-                    nodeList.some((n) => n.id === refId && n.type === 'config') &&
-                    isReachable(edgeList, refId, id)
-                ) {
-                    addConfigRefs(refId, visited)
-                }
-            }
-        }
-        const configVisited = new Set<string>()
-        for (const nid of incomingIds) {
-            const node = nodeList.find((n) => n.id === nid)
-            if (node?.type === 'config') addConfigRefs(nid, configVisited)
-            else out.add(nid)
-        }
-        for (const e of edgeList) {
-            if (out.has(e.target)) out.add(e.source)
-        }
-        return out
-    }, [nodes, edges, id, incomingIds])
-
-    const configSignature = useMemo(
+    const signatures = useMemo(
         () =>
-            (nodes as { id: string; type?: string; data?: unknown }[])
-                .filter((n) => n.type === 'config' && connectedNodeIds.has(n.id))
-                .map((n) => `${n.id}:${(n.data as { title?: string })?.title ?? ''}:${getConfigContent(n.data as Record<string, unknown>)}`)
-                .sort()
-                .join('|'),
-        [nodes, connectedNodeIds]
-    )
-    const edgesSignature = useMemo(
-        () =>
-            (edges as { source: string; target: string }[])
-                .filter(
-                    (e) =>
-                        connectedNodeIds.has(e.source) &&
-                        (connectedNodeIds.has(e.target) || e.target === id)
-                )
-                .map((e) => `${e.source}->${e.target}`)
-                .sort()
-                .join('|'),
-        [edges, connectedNodeIds, id]
-    )
-    const variablesSignature = useMemo(
-        () =>
-            (nodes as { id: string; type?: string; data?: { value?: unknown } }[])
-                .filter((n) => n.type === 'variable' && connectedNodeIds.has(n.id))
-                .map((n) => `${n.id}:${n.data?.value}`)
-                .sort()
-                .join('|'),
-        [nodes, connectedNodeIds]
-    )
-    const functionsSignature = useMemo(
-        () =>
-            (nodes as { id: string; type?: string; data?: { body?: string } }[])
-                .filter((n) => n.type === 'function' && connectedNodeIds.has(n.id))
-                .map((n) => `${n.id}:${n.data?.body ?? ''}`)
-                .sort()
-                .join('|'),
-        [nodes, connectedNodeIds]
-    )
-    const dataSignature = useMemo(
-        () =>
-            (nodes as { id: string; type?: string; data?: { rows?: unknown[]; hiddenColumns?: unknown[] } }[])
-                .filter((n) => n.type === 'data' && connectedNodeIds.has(n.id))
-                .map((n) => `${n.id}:${JSON.stringify(n.data?.rows ?? [])}:${JSON.stringify(n.data?.hiddenColumns ?? [])}`)
-                .sort()
-                .join('|'),
-        [nodes, connectedNodeIds]
-    )
-
-    const sourceSignature = useMemo(
-        () =>
-            JSON.stringify({
-                configSignature,
-                edgesSignature,
-                variablesSignature,
-                functionsSignature,
-                dataSignature,
-            }),
-        [configSignature, edgesSignature, variablesSignature, functionsSignature, dataSignature]
+            buildSourceSignatures(
+                nodes as { id: string; type?: string; data?: unknown }[],
+                edges as { source: string; target: string }[],
+                id,
+                incomingIds
+            ),
+        [nodes, edges, id, incomingIds]
     )
+    const {
+        connectedNodeIds,
+        configSignature,
+        edgesSignature,
+        variablesSignature,
+        functionsSignature,
+        dataSignature,
+        sourceSignature,
+    } = signatures
 
     const lastRunSourceSignature = data?.lastRunSourceSignature
 

frontend/src/lib/graph/renderingSignatures.ts

@@ -0,0 +1,142 @@
+/**
+ * Pure functions to build "connected node ids" and source signatures for the
+ * rendering pipeline. Used by useRenderingNodeState so the hook stays thin and
+ * this logic is testable in isolation.
+ */
+
+import { getConfigContent } from '@/lib/graph/rendering'
+import { isReachable, resolveExtendsRef, getTemplateRefs } from '@/lib/graph/templateRefs'
+
+export type NodeLike = { id: string; type?: string; data?: unknown }
+export type EdgeLike = { source: string; target: string }
+
+/**
+ * Collects all node ids that affect the render: direct incoming nodes plus
+ * config nodes reached via template refs (extends/include/import) that are
+ * reachable to the render node.
+ */
+export function buildConnectedNodeIds(
+  nodes: NodeLike[],
+  edges: EdgeLike[],
+  renderNodeId: string,
+  incomingIds: string[],
+  getContent: (data: Record<string, unknown> | undefined) => string = getConfigContent
+): Set<string> {
+  const out = new Set<string>()
+  const addConfigRefs = (nodeId: string, visited: Set<string>) => {
+    if (visited.has(nodeId)) return
+    const node = nodes.find((n) => n.id === nodeId && n.type === 'config')
+    if (!node) return
+    visited.add(nodeId)
+    out.add(nodeId)
+    const content = getContent((node.data ?? undefined) as Record<string, unknown> | undefined)
+    for (const ref of getTemplateRefs(content)) {
+      const refId = resolveExtendsRef(nodes, ref)
+      if (
+        refId &&
+        nodes.some((n) => n.id === refId && n.type === 'config') &&
+        isReachable(edges, refId, renderNodeId)
+      ) {
+        addConfigRefs(refId, visited)
+      }
+    }
+  }
+  const configVisited = new Set<string>()
+  for (const nid of incomingIds) {
+    const node = nodes.find((n) => n.id === nid)
+    if (node?.type === 'config') addConfigRefs(nid, configVisited)
+    else out.add(nid)
+  }
+  for (const e of edges) {
+    if (out.has(e.target)) out.add(e.source)
+  }
+  return out
+}
+
+export type SourceSignatures = {
+  connectedNodeIds: Set<string>
+  configSignature: string
+  edgesSignature: string
+  variablesSignature: string
+  functionsSignature: string
+  dataSignature: string
+  sourceSignature: string
+}
+
+/**
+ * Builds connected node set and all signatures used to decide when to re-run
+ * the resolve → render pipeline.
+ */
+export function buildSourceSignatures(
+  nodes: NodeLike[],
+  edges: EdgeLike[],
+  renderNodeId: string,
+  incomingIds: string[],
+  getContent: (data: Record<string, unknown> | undefined) => string = getConfigContent
+): SourceSignatures {
+  const connectedNodeIds = buildConnectedNodeIds(
+    nodes,
+    edges,
+    renderNodeId,
+    incomingIds,
+    getContent
+  )
+
+  const configSignature = nodes
+    .filter((n) => n.type === 'config' && connectedNodeIds.has(n.id))
+    .map(
+      (n) =>
+        `${n.id}:${(n.data as { title?: string })?.title ?? ''}:${getContent(n.data as Record<string, unknown>)}`
+    )
+    .sort()
+    .join('|')
+
+  const edgesSignature = edges
+    .filter(
+      (e) =>
+        connectedNodeIds.has(e.source) &&
+        (connectedNodeIds.has(e.target) || e.target === renderNodeId)
+    )
+    .map((e) => `${e.source}->${e.target}`)
+    .sort()
+    .join('|')
+
+  const variablesSignature = nodes
+    .filter((n) => n.type === 'variable' && connectedNodeIds.has(n.id))
+    .map((n) => `${n.id}:${(n.data as { value?: unknown })?.value}`)
+    .sort()
+    .join('|')
+
+  const functionsSignature = nodes
+    .filter((n) => n.type === 'function' && connectedNodeIds.has(n.id))
+    .map((n) => `${n.id}:${(n.data as { body?: string })?.body ?? ''}`)
+    .sort()
+    .join('|')
+
+  const dataSignature = nodes
+    .filter((n) => n.type === 'data' && connectedNodeIds.has(n.id))
+    .map(
+      (n) =>
+        `${n.id}:${JSON.stringify((n.data as { rows?: unknown[] })?.rows ?? [])}:${JSON.stringify((n.data as { hiddenColumns?: unknown[] })?.hiddenColumns ?? [])}`
+    )
+    .sort()
+    .join('|')
+
+  const sourceSignature = JSON.stringify({
+    configSignature,
+    edgesSignature,
+    variablesSignature,
+    functionsSignature,
+    dataSignature,
+  })
+
+  return {
+    connectedNodeIds,
+    configSignature,
+    edgesSignature,
+    variablesSignature,
+    functionsSignature,
+    dataSignature,
+    sourceSignature,
+  }
+}