diff --git a/ui/src/api/queries/commands.ts b/ui/src/api/queries/commands.ts
new file mode 100644
index 00000000..08fdb93b
--- /dev/null
+++ b/ui/src/api/queries/commands.ts
@@ -0,0 +1,21 @@
+import { useMutation } from '@tanstack/react-query'
+import { api } from '../client'
+
+interface SendGroupCommandParams {
+  group: string
+  type: string
+  payload: Record<string, unknown>
+}
+
+export function useSendGroupCommand() {
+  return useMutation({
+    mutationFn: async ({ group, type, payload }: SendGroupCommandParams) => {
+      const { data, error } = await api.POST('/agents/groups/{group}/commands', {
+        params: { path: { group } },
+        body: { type, payload } as any,
+      })
+      if (error) throw new Error('Failed to send command')
+      return data!
+    },
+  })
+}
diff --git a/ui/src/pages/ExchangeDetail/ExchangeDetail.tsx b/ui/src/pages/ExchangeDetail/ExchangeDetail.tsx
index 274004d1..3ef7c3b2 100644
--- a/ui/src/pages/ExchangeDetail/ExchangeDetail.tsx
+++ b/ui/src/pages/ExchangeDetail/ExchangeDetail.tsx
@@ -1,14 +1,16 @@
-import { useState, useMemo } from 'react'
+import { useState, useMemo, useCallback } from 'react'
 import { useParams, useNavigate } from 'react-router'
 import {
   Badge, StatusDot, MonoText, CodeBlock, InfoCallout,
-  ProcessorTimeline, Breadcrumb, Spinner, RouteFlow,
+  ProcessorTimeline, Breadcrumb, Spinner, RouteFlow, useToast,
 } from '@cameleer/design-system'
 import type { ProcessorStep, RouteNode } from '@cameleer/design-system'
 import { useExecutionDetail, useProcessorSnapshot } from '../../api/queries/executions'
 import { useCorrelationChain } from '../../api/queries/correlation'
 import { useDiagramLayout } from '../../api/queries/diagrams'
 import { mapDiagramToRouteNodes } from '../../utils/diagram-mapping'
+import { useTracingStore } from '../../stores/tracing-store'
+import { useSendGroupCommand } from '../../api/queries/commands'
 import styles from './ExchangeDetail.module.css'
 
 // ── Helpers ──────────────────────────────────────────────────────────────────
@@ -130,6 +132,59 @@ export default function ExchangeDetail() {
     }))
   }, [diagram, processors, procList])
 
+  // ProcessorId lookup: timeline index → processorId
+  const processorIds: string[] = useMemo(() => {
+    const ids: string[] = []
+    function walk(node: any) {
+      ids.push(node.processorId || '')
+      if (node.children) node.children.forEach(walk)
+    }
+    procList.forEach(walk)
+    return ids
+  }, [procList])
+
+  // ProcessorId lookup: flow node index → processorId (diagram order)
+  const flowProcessorIds: string[] = useMemo(() => {
+    if (!diagram?.nodes) return processorIds
+    const flatProcs: Array<{ diagramNodeId?: string; processorId?: string }> = []
+    function flatten(nodes: any[]) {
+      for (const n of nodes) {
+        flatProcs.push(n)
+        if (n.children) flatten(n.children)
+      }
+    }
+    flatten(procList)
+    const lookup = new Map(flatProcs
+      .filter(p => p.diagramNodeId && p.processorId)
+      .map(p => [p.diagramNodeId!, p.processorId!]))
+    return diagram.nodes.map(node => lookup.get(node.id ?? '') ?? '')
+  }, [diagram, procList, processorIds])
+
+  // ── Tracing toggle ──────────────────────────────────────────────────────
+  const { toast } = useToast()
+  const tracingStore = useTracingStore()
+  const sendCommand = useSendGroupCommand()
+  const appRoute = detail ? `${detail.applicationName}:${detail.routeId}` : ''
+
+  const handleToggleTracing = useCallback((processorId: string) => {
+    if (!processorId || !detail?.applicationName || !detail?.routeId) return
+    const newSet = tracingStore.toggleProcessor(appRoute, processorId)
+    sendCommand.mutate({
+      group: detail.applicationName,
+      type: 'set-traced-processors',
+      payload: { routeId: detail.routeId, processorIds: Array.from(newSet) },
+    }, {
+      onSuccess: (data) => {
+        const action = newSet.has(processorId) ? 'enabled' : 'disabled'
+        toast({ title: `Tracing ${action}`, description: `${processorId} — sent to ${data?.targetCount ?? 0} agent(s)`, variant: 'success' })
+      },
+      onError: () => {
+        tracingStore.toggleProcessor(appRoute, processorId)
+        toast({ title: 'Command failed', description: 'Could not send tracing command', variant: 'error' })
+      },
+    })
+  }, [detail, appRoute, tracingStore, sendCommand, toast])
+
   // Correlation chain
   const correlatedExchanges = useMemo(() => {
     if (!correlationData?.data || correlationData.data.length <= 1) return []
@@ -287,6 +342,15 @@ export default function ExchangeDetail() {
                 totalMs={detail.durationMs}
                 onProcessorClick={(_proc, index) => setSelectedProcessorIndex(index)}
                 selectedIndex={activeIndex}
+                getActions={(_proc, index) => {
+                  const pid = processorIds[index]
+                  if (!pid || !detail?.applicationName) return []
+                  return [{
+                    label: tracingStore.isTraced(appRoute, pid) ? 'Disable Tracing' : 'Enable Tracing',
+                    onClick: () => handleToggleTracing(pid),
+                    disabled: sendCommand.isPending,
+                  }]
+                }}
               />
             ) : (
               <InfoCallout>No processor data available</InfoCallout>
@@ -297,6 +361,15 @@ export default function ExchangeDetail() {
                 nodes={routeNodes}
                 onNodeClick={(_node, index) => setSelectedProcessorIndex(index)}
                 selectedIndex={activeIndex}
+                getActions={(_node, index) => {
+                  const pid = flowProcessorIds[index]
+                  if (!pid || !detail?.applicationName) return []
+                  return [{
+                    label: tracingStore.isTraced(appRoute, pid) ? 'Disable Tracing' : 'Enable Tracing',
+                    onClick: () => handleToggleTracing(pid),
+                    disabled: sendCommand.isPending,
+                  }]
+                }}
               />
             ) : (
               <Spinner />
diff --git a/ui/src/stores/tracing-store.ts b/ui/src/stores/tracing-store.ts
new file mode 100644
index 00000000..d0791bbe
--- /dev/null
+++ b/ui/src/stores/tracing-store.ts
@@ -0,0 +1,24 @@
+import { create } from 'zustand'
+
+interface TracingState {
+  tracedProcessors: Record<string, Set<string>>
+  isTraced: (appRoute: string, processorId: string) => boolean
+  toggleProcessor: (appRoute: string, processorId: string) => Set<string>
+}
+
+export const useTracingStore = create<TracingState>((set, get) => ({
+  tracedProcessors: {},
+
+  isTraced: (appRoute, processorId) =>
+    get().tracedProcessors[appRoute]?.has(processorId) ?? false,
+
+  toggleProcessor: (appRoute, processorId) => {
+    const current = new Set(get().tracedProcessors[appRoute] ?? [])
+    if (current.has(processorId)) current.delete(processorId)
+    else current.add(processorId)
+    set((state) => ({
+      tracedProcessors: { ...state.tracedProcessors, [appRoute]: current },
+    }))
+    return current
+  },
+}))