Description:

We are experiencing a critical issue with the Gemini Live API using the gemini-2.0-flash-live-001 model, specifically when attempting to use function calling. Starting approximately on Tuesday, May 13, 2025, around 4:00 AM UTC+3, API sessions began to hang indefinitely when a query is made that should trigger a function call.

Symptoms:

• API Hangs: When a prompt intended to trigger a declared function is sent, the API session stops responding. The connection (e.g., WebSocket) appears to remain open, but no further data or responses are received.
• No Tool Call in Response: In the problematic sessions, the expected tool_code or function call invocation is not present in the API response payload before the hang occurs.
• Session Unrecoverable: Once the API session enters this stuck state, it does not respond to any subsequent messages or queries, even simple ones like "hello" or "can you hear me?".
• Issue Start Time: This behavior started manifesting consistently in the last 10-12 hours (from the time of this report). Prior to this, our implementation using tool calls and function calls with gemini-2.0-flash-live-001 was working correctly.

Reproducibility:

• In Production Environment: The issue is consistently reproducible in our product, which relies on the Gemini Live API with function calling.
• In Google AI Studio: We have verified that the same hanging behavior occurs when testing function calls with the gemini-2.0-flash-live-001 model directly within Google AI Studio (https://aistudio.google.com/). This suggests the issue is not isolated to our specific implementation.
• Across Different Contexts: We have tested with different Google accounts, API keys, and have reviewed our implementation to rule out client-side errors. The issue persists across these variables.

Steps to reproduce

1. Define simple basic function call before live API call.
2. Start call and try to trigger a function call with a related question.
3. Until function call triggers, all call seams normal,
4. When you think you trigger function call, Its hang on after that point.

Impact:

This is a critical, production-blocking issue for us as an enterprise customer. Our product's core functionality relies heavily on the function calling capabilities of the Gemini Live API, and it is currently unusable due to this problem.

Expected Behavior:

The Gemini Live API (gemini-2.0-flash-live-001) should:

• Correctly identify when a user prompt is intended to trigger a registered function call.
• Respond with the appropriate tool_code or function call invocation data.
• Continue to be responsive for subsequent turns in the conversation after a function call is processed (or even if one is just requested).

Actual Behavior:

The API session becomes unresponsive when a function call is expected. No function call data is returned, and the session ceases to process any further input.

Request:

We urge the Gemini API team to investigate this issue with high priority. Please provide information on the cause and an estimated timeline for resolution. If there are any recommended workarounds or alternative stable model versions that reliably support function calling for live, streaming interactions, please advise.

Environment details

• Model: gemini-2.0-flash-live-001
• API: Gemini Live API (streaming/interactive sessions)
• Feature: Function Calling / Tool Use
• Client Libraries: We use socket based approach, but SDK based approaches also experiencing same issue.
• Programming language: Python or Any language with REST socket support
• OS: Linux/macOS (Issue independent of OS)
• Language runtime version: Latest
• Package version: Latest

Making sure to follow these steps will guarantee the quickest resolution possible.

Thanks!