n8n Main Workflow Trigger Fails to Pass Prompt to Contact Agent for Email Retrieval

I am trying to retrieve an email address from a Google Sheets file using n8n. When I use the chat trigger with the query

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Can you retrieve Steve Utting’s email address?

it returns the email correctly:

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Steve Utting’s email address is **steve@innertelligence.com.au**

However, initiating the same query via the main workflow returns an error:

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Error: query

Can you retrieve Steve Utting’s email address?

error

No prompt specified

This suggests that the main workflow’s Workflow Input Trigger is not supplying the expected prompt to the Contact Agent node. Below are the workflow segments for reference:

---

Workflow Input Trigger:

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(Select the nodes on your canvas and use the keyboard shortcuts CMD+C/CTRL+C and CMD+V/CTRL+V to copy and paste the workflow.)

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{
  "nodes": [
    {
      "parameters": {
        "inputSource": "passthrough"
      },
      "type": "n8n-nodes-base.executeWorkflowTrigger",
      "typeVersion": 1.1,
      "position": [
        0,
        0
      ],
      "id": "1fb2c696-b85c-4776-8492-3dec481f5ee3",
      "name": "Workflow Input Trigger"
    }
  ],
  "connections": {
    "Workflow Input Trigger": {
      "main": [
        []
      ]
    }
  },
  "pinData": {},
  "meta": {
    "templateCredsSetupCompleted": true,
    "instanceId": "bd6b4409fbf51ffa4ab24c1cfcf2d7f3493d7b12ed95aaa1d2c6f20ebdf49059"
  }
}

Contact Agent Configuration:

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{
  "nodes": [
    {
      "parameters": {
        "options": {
          "systemMessage": "You are a contact agent.  You are responsible for maintaining the list of contacts and retrieving details as needed.\n\n### Available Tools ###\n1. 'Get Contact' - Use this tool to get contact emails and other details.\n2. 'Add or Update Contact' - Use this tool to compare new data and update as necessary as well as to add a completely new record for a contact.\n\n### **Agent Workflow and Rules***\n1. **Identify the Action Type**\n   - Determine whether the request is related to getting contact details, adding new contact details or updating details.\n\n2. **Gather Required Information**\n   - If the task involves a contact, retrieve necessary details using 'Get Contact' before proceeding.\n   - Example: get an email address i.e "Can you retrieve for me Steve Utting's email address ".\n   - If contact information is missing, ask the user for details before proceeding.\n\n3. **Call the Correct Tool**\n   -Pass the user's request to the appropriate too in a structured query format.  For email address query use "Get Contact"\n\n4. **Confirm Task Completion**\n   - Provide a confirmation response once the too has executed the action.\n   -If the tool requires more information, request it from the user before proceeding.\n\n### **Examples of Agent Execution**\n#### **Example 1: Retrieve an email address**\n**User Input:** "can you retrieve Kelvin's email for me."\n\n**Action Steps:**\n1. Use 'Get Contact' to retrieve Kelvin's email address.\n\n---\n\n#### **Example 2: Add a New Contact**\n**User Input:** "Add Kelvin's contact details."\n\n**Action Steps:**\n1. Use 'Add or Update Contact' to add a new contact.\n   - if contact does not exist, add the new contact as a new record.\n   - if the contact exists, check the current details and ukpdate with the new data if necessary.\n\n\n#### **Example 3: Update Contact details**\n**User Input:** "Update Kelvin's phone number with the new number 0417555689."\n1. Call "Add or Update Contact" and check the phone number stored and update with then new one.\n2. Notify User: "Kelvins phone number was updated".\n\n---\n\n### **Error Handling and Clarifications**\n- **Missing Contact Information**\n   - if the action requres an email and it's not found, stop and ask the user before pooceeding.\n- **Tool-Specific Errors:**\n   - if a tool fails to execuete an action, notify the user and provide alternative suggestions.\n- **Ambiguous Requests:**\n   - If a request is unclear, as the suer for clarification.\n\n---\n\n### **Final Notes**\n- Always confirms task completion or requests additional information from the user if needed.\n- Here is the current date/time {{ $now }}"
        }
      },
      "type": "@n8n/n8n-nodes-langchain.agent",
      "typeVersion": 1.7,
      "position": [
        220,
        -160
      ],
      "id": "dd1765c9-5aef-48cd-8e6e-f52c31c2c0d6",
      "name": "Contact Agent",
      "retryOnFail": true,
      "onError": "continueErrorOutput"
    }
  ],
  "connections": {
    "Contact Agent": {
      "main": [
        [],
        []
      ]
    }
  },
  "pinData": {},
  "meta": {
    "templateCredsSetupCompleted": true,
    "instanceId": "bd6b4409fbf51ffa4ab24c1cfcf2d7f3493d7b12ed95aaa1d2c6f20ebdf49059"
  }
}

Get Contact Node (Google Sheets):

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{
  "nodes": [
    {
      "parameters": {
        "documentId": {
          "__rl": true,
          "value": "16XL0MiUHYldeyGq3Ow7pM7bKRQlXTs0DrFCI4-rqwO8",
          "mode": "list",
          "cachedResultName": "Contacts-new",
          "cachedResultUrl": "https://docs.google.com/spreadsheets/d/16XL0MiUHYldeyGq3Ow7pM7bKRQlXTs0DrFCI4-rqwO8/edit?usp=drivesdk"
        },
        "sheetName": {
          "__rl": true,
          "value": 22910942,
          "mode": "list",
          "cachedResultName": "contacts-refined",
          "cachedResultUrl": "https://docs.google.com/spreadsheets/d/16XL0MiUHYldeyGq3Ow7pM7bKRQlXTs0DrFCI4-rqwO8/edit#gid=22910942"
        },
        "filtersUI": {
          "values": [
            {
              "lookupColumn": "First Name",
              "lookupValue": "={{  $fromAI("firstName") }}"
            },
            {
              "lookupColumn": "Last Name",
              "lookupValue": "={{ $fromAI("surName") }}"
            }
          ]
        },
        "options": {}
      },
      "type": "n8n-nodes-base.googleSheetsTool",
      "typeVersion": 4.5,
      "position": [
        340,
        100
      ],
      "id": "1902570a-5efc-490e-9caa-d93932f0dd53",
      "name": "Get Contact",
      "credentials": {
        "googleSheetsOAuth2Api": {
          "id": "3UZ0kGcCmWGhEeU1",
          "name": "Google Sheets account 3"
        }
      }
    }
  ],
  "connections": {
    "Get Contact": {
      "ai_tool": [
        []
      ]
    }
  },
  "pinData": {},
  "meta": {
    "templateCredsSetupCompleted": true,
    "instanceId": "bd6b4409fbf51ffa4ab24c1cfcf2d7f3493d7b12ed95aaa1d2c6f20ebdf49059"
  }
}

Based on the error, my hypothesis is that the data from the main workflow is missing the prompt, which is required by the Contact Agent node. I need to adjust the input payload or variable mapping so that the prompt is properly passed along.

Any suggestions or solutions to ensure the prompt is included when using the main workflow trigger?