ollama - 💡(How to fix) Fix Ollama Cloud: Gemini 3 tool-calling fails (missing thought_signature) [1 participants]

Error: This error is specific to Gemini 3's safety mechanism which requires a thought_signature to be preserved across tool-calling turns. It appears the Ollama native API (/api/chat) currently doesn't expose or persist this signature when proxying Gemini 3 models, making tool-calling impossible for Gemini 3 on the cloud platform.

Fix Plan

To resolve the issue, we need to modify the Ollama Cloud API to persist or expose the thought_signature for Gemini 3 models.

Steps to Fix

• Modify the API endpoint /api/chat to include the thought_signature in the response.
• Update the client-side code to store and return the thought_signature in subsequent requests.

Example Code

# Server-side (Ollama Cloud API)
from flask import jsonify

@app.route('/api/chat', methods=['POST'])
def chat():
    # ... existing code ...
    response = {
        'tool_call': tool_call,
        'thought_signature': thought_signature  # Add this line
    }
    return jsonify(response)

# Client-side (OpenClaw)
import requests

def send_tool_call(tool_call, thought_signature):
    response = requests.post('https://ollama.com/api/chat', json={
        'tool_call': tool_call,
        'thought_signature': thought_signature  # Add this line
    })
    return response.json()

Verification

To verify the fix, test the API endpoint with a Gemini 3 model and check that the thought_signature is included in the response. Then, send a subsequent request with the stored thought_signature and verify that the API returns a successful response (200 OK).

Extra Tips

• Ensure that the thought_signature is properly validated and sanitized to prevent security vulnerabilities.
• Consider implementing a caching mechanism to store the thought_signature for each conversation, in case the client-side storage fails.