Tool Node inside Iteration Node fails with schema error when using {{ $iteration }} variable from JSON array of objects

Description

When a Tool Node is placed inside an Iteration Node, it cannot accept the {{ $iteration }} variable as input when iterating over a JSON array of objects. The error Error: Received tool input did not match expected schema occurs. This issue only happens with JSON arrays of objects - simple arrays work fine.

Current Behavior

The Iteration Node successfully processes JSON arrays containing objects:

[
  {
    "produktName": "Wireless Gaming Maus X-Pro",
    "produktNummer": "WGM-2024-001",
    "preis": 79.99,
    "lagerbestand": 145
  },
  {
    "produktName": "Bluetooth Kopfhörer SoundWave",
    "produktNummer": "BKH-2024-042",
    "preis": 129.50,
    "lagerbestand": 67
  },
  {
    "produktName": "USB-C Ladekabel Premium 2m",
    "produktNummer": "LKB-2024-315",
    "preis": 24.99,
    "lagerbestand": 523
  }
]

• When using a Direct Reply node inside the iteration, {{ $iteration }} correctly outputs individual objects (one complete product with all its properties per iteration) ✅

• When using a Tool Node inside the iteration with {{ $iteration }} as an input argument value, the tool fails with: Error: Received tool input did not match expected schema ❌

Screenshots

Iteration not working:

Showing Iteration working with JSON Array, no error messages:

Expected Behavior

The Tool Node should accept {{ $iteration }} as input when iterating over JSON objects, just like the Direct Reply node does. The current iteration's object should be passed to the tool in a format that matches the expected schema.

Steps to Reproduce

1. Create an Iteration Node with a JSON array of objects as input
2. Add a Tool Node inside the Iteration Node
3. Configure the Tool Node with a custom tool
4. Set the Tool Input Argument Value to {{ $iteration }}
5. Execute the workflow
6. Observe the schema validation error on the Tool Node

Comparison

• Simple arrays (e.g., [1,2,3,4,5]): Work correctly with Tool Node ✅
• JSON object arrays: Fail with schema error when used with Tool Node ❌
• Direct Reply node: Works correctly with both simple and JSON object arrays ✅

Environment

Use Method: Self-hosted Enterprise
Flowise Version: v2
Operating System: Windows
Browser: Chrome

Additional Context

here is the example flow from the screenshots and the custom tool:

Testing-CustomTool.json
Bug Reporting Agents.json