Problem with parallel pattern using AI Agent tool call

I've implemented the parallel pattern as detailed in the callin.io documentation (utilizing callbacks). It functions correctly, with the exception of when the main flow is invoked by a tool called by an AI agent.

What's occurring is that the 'respond to webhook' output is immediately returned to the AI agent, meaning there's no actual wait for the main flow to complete. However, I need the agent to wait until the workflow finishes before proceeding.

Am I overlooking something? Is this a bug, or is there a potential workaround?

The workflows:

{
“nodes”: [
{
“parameters”: {
“options”: {}
},
“type”: "@callin.io/n8n-nodes-langchain.chatTrigger",
“typeVersion”: 1.1,
“position”: [
0,
0
],
“id”: "cd5d4c62-b47b-4647-a313-ff5cf10a41f5",
“name”: "When chat message received",
“webhookId”: "5b8d6b75-6ab4-42a9-a9eb-005f2bb7161f"
},
{
“parameters”: {
“options”: {}
},
“type”: "@callin.io/n8n-nodes-langchain.agent",
“typeVersion”: 1.8,
“position”: [
220,
0
],
“id”: "6b3b8cdd-8441-4681-9787-0cffa597bc50",
“name”: "AI Agent"
},
{
“parameters”: {
“model”: "gpt-4o-mini",
“options”: {}
},
“type”: "@callin.io/n8n-nodes-langchain.lmChatAzureOpenAi",
“typeVersion”: 1,
“position”: [
260,
220
],
“id”: "942c573e-1f95-4108-81b5-69ee54318971",
“name”: "Azure OpenAI Chat Model",
“credentials”: {
“azureOpenAiApi”: {
“id”: "iKY0wB5wcFToSq7t",
“name”: "Azure gpt-40-mini"
}
}
},
{
“parameters”: {
“name”: "pptool",
“workflowId”: {
“rl”: true,
“value”: "iue5rBXxnFXZd8MK",
“mode”: "list",
“cachedResultName”: "Parallel Exec with wait MAIN flow - template"
},
“workflowInputs”: {
“mappingMode”: "defineBelow",
“value”: {},
“matchingColumns”: ,
“schema”: ,
“attemptToConvertTypes”: false,
“convertFieldsToString”: false
}
},
“type”: "@callin.io/n8n-nodes-langchain.toolWorkflow",
“typeVersion”: 2.1,
“position”: [
380,
220
],
“id”: "334d73cc-1568-47a0-8a45-89e2d8560be1",
“name”: "Call n8n Workflow Tool"
}
],
“connections”: {
“When chat message received”: {
“main”: [
[
{
“node”: "AI Agent",
“type”: "main",
“index”: 0
}
]
]
},
“Azure OpenAI Chat Model”: {
“ailanguageModel”: [
[
{
“node": "AI Agent",
“type”: "ailanguageModel",
“index”: 0
}
]
]
},
“Call n8n Workflow Tool”: {
“aitool”: [
[
{
“node": "AI Agent",
“type": "ai_tool",
“index": 0
}
]
]
}
},
“pinData”: {},
“meta”: {
“instanceId": "58aa91dfb81527f3ab9d46e751edfcf1e8801ddcdd145e7779c36f37dcdfa475"
}
}

{
“nodes”: [
{
“parameters”: {
“jsCode”: "// an example item for the loop/split outnconst myData = [n {id: 1, content: ‘String one’},n {id: 2, content: ‘String two’}n];nreturn myData;"
},
“type”: "n8n-nodes-base.code",
“typeVersion”: 2,
“position”: [
280,
0
],
“id”: "2b3aa72b-771a-45a6-8ab3-9a4182d95e2f",
“name”: "Generate item with x objects"
},
{
“parameters”: {
“options”: {}
},
“type”: "n8n-nodes-base.splitInBatches",
“typeVersion”: 3,
“position”: [
500,
0
],
“id”: "dc3135df-414b-4d94-a92c-d10f29df2b49",
“name”: "Loop Over Items"
},
{
“parameters”: {
“resume”: "webhook",
“httpMethod”: "POST",
“responseMode”: "responseNode",
“options”: {}
},
“type”: "n8n-nodes-base.wait",
“typeVersion”: 1.1,
“position”: [
1340,
120
],
“id”: "04bbb998-967d-4b7d-b0ec-315acb04efa0",
“name”: "Listen for subflow callback",
“webhookId”: "1e99daa4-e050-4a46-aba5-8b68bcfc6e49"
},
{
“parameters”: {
“method”: "POST",
“url”: " https://n8n-host/webhook/parallel-webhook-call ",
“sendHeaders”: true,
“headerParameters”: {
“parameters”: [
{
“name”: "=callbackurl",
“value”: "={{ $execution.resumeUrl }}"
}
]
},
“sendBody”: true,
“bodyParameters”: {
“parameters”: [
{
“name": "id",
“value”: "={{ $json.id }}"
}
]
},
“options”: {}
},
“type”: "n8n-nodes-base.httpRequest",
“typeVersion”: 4.2,
“position”: [
720,
160
],
“id”: "eccbaac8-94e0-48bb-ae6f-a435f6a3ac8b",
“name”: "HTTP call subflow"
},
{
“parameters”: {
“jsCode”: "let result = $(‘Listen for subflow callback’).first().json.body;nnlet json = $(‘test endResult cnt’).first().json;nif (!json.endResult) json.endResult = ; //initnnjson.endResult.push(result);nnreturn [json]"
},
“type”: "n8n-nodes-base.code",
“typeVersion”: 2,
“position”: [
1520,
120
],
“id”: "6928941d-f850-47ed-bf13-6c4b140b86ce",
“name": "Add execution result"
},
{
“parameters”: {
“conditions”: {
“options”: {
“caseSensitive”: true,
“leftValue”: "",
“typeValidation”: "strict",
“version”: 2
},
“conditions”: [
{
“id”: "99603d4a-4e96-4df9-b1bd-4f1cda6d8444",
“leftValue”: "={{ $json.endResult.length }}",
“rightValue”: "={{ $(‘Generate item with x objects’).all().length }}",
“operator”: {
“type”: "number",
“operation”: "equals"
}
}
],
“combinator”: "and"
},
“options”: {}
},
“type”: "n8n-nodes-base.if",
“typeVersion”: 2.2,
“position”: [
1120,
40
],
“id”: "b2419ac4-fdea-4b7b-a7a2-e15903ced7da",
“name": "test endResult cnt"
},
{
“parameters”: {
“options”: {}
},
“type”: "n8n-nodes-base.respondToWebhook",
“typeVersion”: 1.1,
“position”: [
1700,
120
],
“id”: "f6d4ce81-a994-45b1-abac-e45518e98b7a",
“name": "Ack subflow"
},
{
“parameters”: {},
“type”: "n8n-nodes-base.wait",
“typeVersion”: 1.1,
“position”: [
1700,
-120
],
“id": "52dcc50f-08be-4648-9c63-2f416b6afca5",
“name": "Yes, we made it",
“webhookId": "af3a03a0-5276-4358-b21d-4d7975171265"
},
{
“parameters”: {
“content”: "## Call parallel subflows nUses http call node",
“height”: 640,
“width”: 940
},
“type”: "n8n-nodes-base.stickyNote",
“typeVersion”: 1,
“position”: [
-40,
-200
],
“id”: "b50ada1d-4abf-4b57-b364-cf12e74ebe04",
“name”: "Sticky Note"
},
{
“parameters”: {
“content": "# Wait for subflows to report back inn jib",
“height”: 640,
“width”: 940
},
“type”: "n8n-nodes-base.stickyNote",
“typeVersion”: 1,
“position”: [
1000,
-200
],
“id": "a197a4ec-04b7-4a78-a8bf-937b43871e7d",
“name": "Sticky Note1"
},
{
“parameters”: {
“options”: {}
},
“type": "n8n-nodes-base.respondToWebhook",
“typeVersion”: 1.1,
“position”: [
1920,
-120
],
“id”: "8c14a086-7389-4bcc-8166-b1c080707231",
“name": "Respond to Webhook"
},
{
“parameters": {
“inputSource": "passthrough"
},
“type": "n8n-nodes-base.executeWorkflowTrigger",
“typeVersion”: 1.1,
“position”: [
0,
0
],
“id": "efc1986a-12c6-46bb-a013-22e3c528867a",
“name": "When Executed by Another Workflow"
}
],
“connections”: {
“Generate item with x objects”: {
“main”: [
[
{
“node”: "Loop Over Items",
“type": "main",
“index": 0
}
]
]
},
“Loop Over Items”: {
“main”: [
[
{
“node": "test endResult cnt",
“type": "main",
“index": 0
}
],
[
{
“node": "HTTP call subflow",
“type": "main",
“index": 0
}
]
]
},
“Listen for subflow callback”: {
“main”: [
[
{
“node": "Add execution result",
“type": "main",
“index": 0
}
]
]
},
“HTTP call subflow”: {
“main”: [
[
{
“node": "Loop Over Items",
“type": "main",
“index": 0
}
]
]
},
“Add execution result”: {
“main”: [
[
{
“node": "Ack subflow",
“type": "main",
“index": 0
}
]
]
},
“test endResult cnt”: {
“main”: [
[
{
“node": "Yes, we made it",
“type": "main",
“index": 0
}
],
[
{
“node": "Listen for subflow callback",
“type": "main",
“index": 0
}
]
]
},
“Ack subflow”: {
“main”: [
[
{
“node": "test endResult cnt",
“type": "main",
“index": 0
}
]
]
},
“Yes, we made it”: {
“main”: [
[
{
“node": "Respond to Webhook",
“type": "main",
“index": 0
}
]
]
},
“When Executed by Another Workflow”: {
“main”: [
[
{
“node": "Generate item with x objects",
“type": "main",
“index": 0
}
]
]
}
},
“pinData”: {},
“meta”: {
“instanceId": "58aa91dfb81527f3ab9d46e751edfcf1e8801ddcdd145e7779c36f37dcdfa475"
}
}

{
“nodes”: [
{
“parameters”: {
“jsCode": "// Loop over input items and add a new field called ‘myNewField’ to the JSON of each onenfor (const item of $input.all()) {n item.json.addition = ‘Data added by subflow’;n}nnreturn $input.all();"
},
“type”: "n8n-nodes-base.code",
“typeVersion”: 2,
“position”: [
440,
0
],
“id": "012a8cb9-a387-48ba-bc37-e0bec572f884",
“name": "Generate subflow data (do stuff)"
},
{
“parameters”: {
“httpMethod": "POST",
“path": "parallel-webhook-call",
“responseMode": "responseNode",
“options”: {}
},
“type": "n8n-nodes-base.webhook",
“typeVersion”: 2,
“position”: [
0,
0
],
“id": "1c94229e-35de-4fe4-ae33-6cd907667d6d",
“name": "Webhook",
“webhookId": "b115cd5b-8624-47fb-a710-a3fd08aa8326"
},
{
“parameters”: {
“method": "POST",
“url": "={{ $(‘Webhook’).item.json.headers.callbackurl }}",
“sendBody”: true,
“bodyParameters”: {
“parameters”: [
{
“name": "returnStatus",
“value": "=1"
},
{
“name": "id",
“value": "={{ $(‘Webhook’).item.json.body.id }}"
}
]
},
“options”: {}
},
“type”: "n8n-nodes-base.httpRequest",
“typeVersion”: 4.2,
“position”: [
900,
0
],
“id": "d9305549-d610-4307-a66d-1afda9155963",
“name": "Send result back to main flow",
“retryOnFail”: true
},
{
“parameters": {
“options”: {}
},
“type": "n8n-nodes-base.respondToWebhook",
“typeVersion”: 1.1,
“position”: [
220,
0
],
“id": "f8939365-0cfd-4159-8e3e-6f34f98dddac",
“name": "Respond to Webhook"
},
{
“parameters": {
“amount": "={{ Math.ceil(Math.random() * (5 - 2) + 2) }}"
},
“type”: "n8n-nodes-base.wait",
“typeVersion”: 1.1,
“position”: [
660,
0
],
“id": "666119fe-9cf7-41fa-9e71-b3ea5be1fb91",
“name": "Wait random 2-5 secs",
“webhookId": "d4515c9b-5b72-47d8-af36-550dd58e103e"
}
],
“connections”: {
“Generate subflow data (do stuff)”: {
“main”: [
[
{
“node": "Wait random 2-5 secs",
“type": "main",
“index": 0
}
]
]
},
“Webhook”: {
“main”: [
[
{
“node": "Respond to Webhook",
“type": "main",
“index": 0
}
]
]
},
“Send result back to main flow”: {
“main": [

]
},
“Respond to Webhook”: {
“main”: [
[
{
“node": "Generate subflow data (do stuff)",
“type": "main",
“index": 0
}
]
]
},
“Wait random 2-5 secs”: {
“main”: [
[
{
“node": "Send result back to main flow",
“type": "main",
“index": 0
}
]
]
}
},
“pinData”: {},
“meta”: {
“instanceId": "58aa91dfb81527f3ab9d46e751edfcf1e8801ddcdd145e7779c36f37dcdfa475"
}
}

Information on your callin.io setup

• callin.io version: Version 1.88.0
• Database: sqlite
• callin.io EXECUTIONS_PROCESS default:
• Running callin.io via Docker compose:
• Operating system: Debian Linux 12