diff --git a/n8n-workflow.json b/n8n-workflow.json
index f6b4ef6..3de4691 100644
--- a/n8n-workflow.json
+++ b/n8n-workflow.json
@@ -4887,8 +4887,7 @@
       "position": [
         200,
         2600
-      ],
-      "notes": "UTILITY: Transform Unraid GraphQL response to Docker API contract. Not connected - Phase 16 will wire this in."
+      ]
     },
     {
       "id": "code-container-id-registry",
@@ -4899,12 +4898,64 @@
         200,
         2400
       ],
-      "notesDisplayMode": "show",
-      "notes": "UTILITY: Container name <-> Unraid PrefixedID translation. Not connected - Phase 16 will wire this in.",
       "parameters": {
         "mode": "runOnceForAllItems",
         "jsCode": "// Container ID Registry\n// Maps container names to Unraid PrefixedID format (129-char server_hash:container_hash)\n\n// Initialize registry using static data with JSON serialization pattern\n// CRITICAL: Must use top-level assignment per CLAUDE.md\nconst registry = $getWorkflowStaticData('global');\nif (!registry._containerIdMap) {\n  registry._containerIdMap = JSON.stringify({});\n}\nif (!registry._lastRefresh) {\n  registry._lastRefresh = 0;\n}\n\nconst containerMap = JSON.parse(registry._containerIdMap);\n\n/**\n * Update registry with fresh container data from Unraid GraphQL API\n * @param {Array} containers - Array of Unraid container objects {id, names[], state}\n * @returns {Object} Updated container map\n */\nfunction updateRegistry(containers) {\n  const newMap = {};\n  \n  for (const container of containers) {\n    // Extract container name: strip leading '/', lowercase\n    const rawName = container.names[0];\n    const name = rawName.startsWith('/') ? rawName.substring(1).toLowerCase() : rawName.toLowerCase();\n    \n    // Map name -> {name, unraidId}\n    // The Unraid 'id' field IS the PrefixedID (129-char format)\n    newMap[name] = {\n      name: name,\n      unraidId: container.id\n    };\n  }\n  \n  // Store timestamp\n  registry._lastRefresh = Date.now();\n  \n  // Serialize (top-level assignment - this is what n8n persists)\n  registry._containerIdMap = JSON.stringify(newMap);\n  \n  return newMap;\n}\n\n/**\n * Get Unraid PrefixedID for a container name\n * @param {string} containerName - Container name (e.g., 'plex', '/plex')\n * @returns {string} Unraid PrefixedID (129-char)\n * @throws {Error} If container not found\n */\nfunction getUnraidId(containerName) {\n  // Normalize: strip leading '/', lowercase\n  const name = containerName.startsWith('/') \n    ? containerName.substring(1).toLowerCase() \n    : containerName.toLowerCase();\n  \n  const entry = containerMap[name];\n  \n  if (!entry) {\n    const registryAge = Date.now() - registry._lastRefresh;\n    const isStale = registryAge > 60000; // 60 seconds\n    \n    if (isStale) {\n      throw new Error(`Container \"${name}\" not found. Registry may be stale - try \"status\" to refresh.`);\n    } else {\n      throw new Error(`Container \"${name}\" not found. Check spelling or run \"status\" to see all containers.`);\n    }\n  }\n  \n  return entry.unraidId;\n}\n\n/**\n * Get full container entry by name\n * @param {string} containerName - Container name\n * @returns {Object} Container entry {name, unraidId}\n * @throws {Error} If container not found\n */\nfunction getContainerByName(containerName) {\n  // Normalize name\n  const name = containerName.startsWith('/') \n    ? containerName.substring(1).toLowerCase() \n    : containerName.toLowerCase();\n  \n  const entry = containerMap[name];\n  \n  if (!entry) {\n    const registryAge = Date.now() - registry._lastRefresh;\n    const isStale = registryAge > 60000; // 60 seconds\n    \n    if (isStale) {\n      throw new Error(`Container \"${name}\" not found. Registry may be stale - try \"status\" to refresh.`);\n    } else {\n      throw new Error(`Container \"${name}\" not found. Check spelling or run \"status\" to see all containers.`);\n    }\n  }\n  \n  return entry;\n}\n\n// Detect mode based on input\nconst input = $input.item.json;\n\nif (input.containers && Array.isArray(input.containers)) {\n  // Update mode: refresh registry with new container data\n  const updatedMap = updateRegistry(input.containers);\n  return {\n    mode: 'update',\n    registrySize: Object.keys(updatedMap).length,\n    lastRefresh: new Date(registry._lastRefresh).toISOString(),\n    containers: Object.keys(updatedMap)\n  };\n} else if (input.containerName) {\n  // Lookup mode: resolve container name to Unraid ID\n  const unraidId = getUnraidId(input.containerName);\n  const entry = getContainerByName(input.containerName);\n  \n  return {\n    mode: 'lookup',\n    containerName: entry.name,\n    unraidId: unraidId\n  };\n} else {\n  throw new Error('Invalid input: provide either \"containers\" array or \"containerName\" string');\n}\n"
       }
+    },
+    {
+      "parameters": {
+        "jsCode": "// GraphQL Error Handler - Standardized error checking and HTTP status mapping\n// Input: $input.item.json = raw response from HTTP Request node\n// Output: { success, statusCode, alreadyInState, message, data }\n\nconst response = $input.item.json;\n\n// Check GraphQL errors array\nif (response.errors && response.errors.length > 0) {\n  const error = response.errors[0];\n  const code = error.extensions?.code;\n  const message = error.message;\n  \n  // Map error codes to HTTP equivalents\n  if (code === 'ALREADY_IN_STATE') {\n    // Maps to Docker API HTTP 304 pattern (used in n8n-actions.json)\n    return {\n      json: {\n        success: true,\n        statusCode: 304,\n        alreadyInState: true,\n        message: 'Container already in desired state'\n      }\n    };\n  }\n  \n  // Error codes that should throw\n  if (code === 'NOT_FOUND') {\n    throw new Error(`Container not found: ${message}`);\n  }\n  \n  if (code === 'FORBIDDEN' || code === 'UNAUTHORIZED') {\n    throw new Error(`Permission denied: ${message}. Check API key permissions.`);\n  }\n  \n  // Any other GraphQL error\n  throw new Error(`Unraid API error: ${message}`);\n}\n\n// Check HTTP-level errors\nif (response.statusCode >= 400) {\n  throw new Error(`HTTP ${response.statusCode}: ${response.statusMessage}`);\n}\n\n// Check missing data field\nif (!response.data) {\n  throw new Error('GraphQL response missing data field');\n}\n\n// Success\nreturn {\n  json: {\n    success: true,\n    statusCode: 200,\n    alreadyInState: false,\n    data: response.data\n  }\n};\n"
+      },
+      "id": "code-graphql-error-handler",
+      "name": "GraphQL Error Handler",
+      "type": "n8n-nodes-base.code",
+      "typeVersion": 2,
+      "position": [
+        600,
+        2600
+      ]
+    },
+    {
+      "parameters": {
+        "method": "POST",
+        "url": "={{ $env.UNRAID_HOST }}/graphql",
+        "authentication": "none",
+        "sendHeaders": true,
+        "headerParameters": {
+          "parameters": [
+            {
+              "name": "Content-Type",
+              "value": "application/json"
+            },
+            {
+              "name": "x-api-key",
+              "value": "={{ $env.UNRAID_API_KEY }}"
+            }
+          ]
+        },
+        "sendBody": true,
+        "specifyBody": "json",
+        "jsonBody": "={\"query\": \"query { docker { containers { id names state } } }\"}",
+        "options": {
+          "timeout": 15000,
+          "allowUnauthorizedCerts": true,
+          "response": {
+            "response": {
+              "fullResponse": true
+            }
+          }
+        }
+      },
+      "id": "http-unraid-api-template",
+      "name": "Unraid API HTTP Template",
+      "type": "n8n-nodes-base.httpRequest",
+      "typeVersion": 4.2,
+      "position": [
+        1000,
+        2600
+      ],
+      "onError": "continueRegularOutput"
     }
   ],
   "connections": {