Tools not working with gpt-4o

[paulotkh]

Hi everyone,

I've been trying to run tool actions with GPT-4o, but it's not working. I created an agent, assigned the GPT-4o model, and added the DALL·E 3 tool (or any other tool), but when I prompt it, I receive an error:

However, when I switch the model to Sonnet 3.7, tool actions work perfectly fine:

The same issue occurs with other tools, such as the calculator:

After some investigation, it seems that when using GPT-4o, it generates the tool-specific prompt (e.g., for DALLE 3) but does not actually trigger the tool execution.
I added extra logging to AgentClient: await run.processStream to check if the tool execution starts. When using Sonnet 3.7, the tool execution works as expected, but with GPT-4o, the tool call is never triggered.

Looking forward to any replies! Any insights on whether this is a bug or if additional configuration is needed would be greatly appreciated.