diff --git a/ui/detection-app/src/App.vue b/ui/detection-app/src/App.vue
index 2e15a97..4686056 100644
--- a/ui/detection-app/src/App.vue
+++ b/ui/detection-app/src/App.vue
@@ -16,8 +16,10 @@ import { usePipelineStore } from './stores/pipeline'
 import { useSSEConnection } from './composables/useSSEConnection'
 import { useCheckpointLoader } from './composables/useCheckpointLoader'
 import { useEditorState } from './composables/useEditorState'
+import { useHashRouter } from './composables/useHashRouter'
 
 const pipeline = usePipelineStore()
+useHashRouter()
 const logPanel = ref<{ clear: () => void } | null>(null)
 
 // SSE connection + pipeline status
diff --git a/ui/detection-app/src/composables/useHashRouter.ts b/ui/detection-app/src/composables/useHashRouter.ts
new file mode 100644
index 0000000..12b64e4
--- /dev/null
+++ b/ui/detection-app/src/composables/useHashRouter.ts
@@ -0,0 +1,70 @@
+import { watch, onUnmounted } from 'vue'
+import { usePipelineStore } from '../stores/pipeline'
+
+/**
+ * Bidirectional sync between URL hash and pipeline store layout state.
+ *
+ * Hash format:
+ *   #/                     → normal dashboard
+ *   #/editor/<stage>       → bbox/region editor for that stage
+ *   #/config/<stage>       → stage config editor
+ *   #/source               → source selector
+ *
+ * Call once in App.vue. Handles popstate (back/forward) and
+ * updates the hash when store state changes.
+ */
+export function useHashRouter() {
+  const pipeline = usePipelineStore()
+
+  function parseHash(hash: string) {
+    const path = hash.replace(/^#\/?/, '')
+    if (!path || path === 'dashboard') {
+      return { mode: 'normal', stage: null as string | null }
+    }
+    if (path === 'source') {
+      return { mode: 'source_selector', stage: null as string | null }
+    }
+    const editorMatch = path.match(/^editor\/(.+)$/)
+    if (editorMatch) {
+      return { mode: 'bbox_editor', stage: editorMatch[1] }
+    }
+    const configMatch = path.match(/^config\/(.+)$/)
+    if (configMatch) {
+      return { mode: 'stage_editor', stage: configMatch[1] }
+    }
+    return { mode: 'normal', stage: null as string | null }
+  }
+
+  function applyHash() {
+    const { mode, stage } = parseHash(window.location.hash)
+    pipeline.layoutMode = mode
+    pipeline.editorStage = stage
+  }
+
+  function updateHash() {
+    let hash = '#/'
+    if (pipeline.layoutMode === 'bbox_editor' && pipeline.editorStage) {
+      hash = `#/editor/${pipeline.editorStage}`
+    } else if (pipeline.layoutMode === 'stage_editor' && pipeline.editorStage) {
+      hash = `#/config/${pipeline.editorStage}`
+    } else if (pipeline.layoutMode === 'source_selector') {
+      hash = '#/source'
+    }
+    if (window.location.hash !== hash) {
+      window.history.pushState(null, '', hash)
+    }
+  }
+
+  // Sync hash → state on load
+  applyHash()
+
+  // Sync hash → state on back/forward
+  window.addEventListener('popstate', applyHash)
+  onUnmounted(() => window.removeEventListener('popstate', applyHash))
+
+  // Sync state → hash when layout changes
+  watch(
+    () => [pipeline.layoutMode, pipeline.editorStage],
+    updateHash,
+  )
+}
diff --git a/ui/detection-app/src/stores/pipeline.ts b/ui/detection-app/src/stores/pipeline.ts
index fc17939..f1e1246 100644
--- a/ui/detection-app/src/stores/pipeline.ts
+++ b/ui/detection-app/src/stores/pipeline.ts
@@ -1,17 +1,12 @@
 /**
  * Pipeline store — run state, transport controls, checkpoint status.
  *
- * Layout is driven by URL hash:
- *   #/                     → normal dashboard
- *   #/editor/<stage>       → bbox/region editor for that stage
- *   #/config/<stage>       → stage config editor
- *   #/source               → source selector
- *
  * State shape defined in types/store-state.ts.
+ * Hash routing is handled by useHashRouter composable, not here.
  */
 
 import { defineStore } from 'pinia'
-import { ref, computed, watch } from 'vue'
+import { ref, computed } from 'vue'
 import type { NodeState } from '../types/store-state'
 import type { CheckpointInfo } from '../types/sse-contract'
 
@@ -26,7 +21,6 @@ export const usePipelineStore = defineStore('pipeline', () => {
   const checkpoints = ref<CheckpointInfo[]>([])
   const error = ref<string | null>(null)
 
-  // Layout mode — synced with URL hash
   const layoutMode = ref<string>('normal')
   const editorStage = ref<string | null>(null)
 
@@ -35,56 +29,6 @@ export const usePipelineStore = defineStore('pipeline', () => {
   const canReplay = computed(() => checkpoints.value.length > 0)
   const isEditing = computed(() => layoutMode.value !== 'normal')
 
-  // --- Hash routing ---
-
-  function parseHash(hash: string) {
-    const path = hash.replace(/^#\/?/, '')
-    if (!path || path === 'dashboard') {
-      return { mode: 'normal', stage: null }
-    }
-    if (path === 'source') {
-      return { mode: 'source_selector', stage: null }
-    }
-    const editorMatch = path.match(/^editor\/(.+)$/)
-    if (editorMatch) {
-      return { mode: 'bbox_editor', stage: editorMatch[1] }
-    }
-    const configMatch = path.match(/^config\/(.+)$/)
-    if (configMatch) {
-      return { mode: 'stage_editor', stage: configMatch[1] }
-    }
-    return { mode: 'normal', stage: null }
-  }
-
-  function applyHash() {
-    const { mode, stage } = parseHash(window.location.hash)
-    layoutMode.value = mode
-    editorStage.value = stage
-  }
-
-  function updateHash() {
-    let hash = '#/'
-    if (layoutMode.value === 'bbox_editor' && editorStage.value) {
-      hash = `#/editor/${editorStage.value}`
-    } else if (layoutMode.value === 'stage_editor' && editorStage.value) {
-      hash = `#/config/${editorStage.value}`
-    } else if (layoutMode.value === 'source_selector') {
-      hash = '#/source'
-    }
-    if (window.location.hash !== hash) {
-      window.history.pushState(null, '', hash)
-    }
-  }
-
-  // Sync hash → state on load and popstate (back/forward)
-  applyHash()
-  window.addEventListener('popstate', applyHash)
-
-  // Sync state → hash when layout changes
-  watch([layoutMode, editorStage], updateHash)
-
-  // --- Actions ---
-
   function setJob(id: string) {
     jobId.value = id
   }