Upload via chat is not working

I'm building an agent to control the content of a KB in Pinecone.
I have a tool that uploads files into this database. But every time I send a file into chat, this happens:
<img width="725" height="324" alt="Image" src="https://github.com/user-attachments/assets/f4a3f5c9-dfe5-4d37-bc3e-11b10a154199" />