print the error sent from the server

[chuenlok]

What does this PR do?

The assert errors from the server are not returned to the client and hid by the 500 internal server error. Updated the server code (https://github.com/meta-llama/llama-stack/pull/493) to send the error and this client can print the error.

• [x] Addresses issue (#434)

Test Plan

Please describe:

• tests you ran to verify your changes with result summaries.
• provide instructions so it can be reproduced.

1. Kick off the server with llama stack run /Users/henrytai/.llama/distributions/llamastack-ollama/ollama-run.yaml --port 5050
2. Trigger an error case from client. The example is PYTHONPATH=. python -m examples.agents.client localhost 5050 from the llama-stack-apps repo. The issue details: "This is a known issue with Llama3.2-3B-Instruct on ollama, where the model produces bad tool calling outputs. In this case, the server agent fails due to assert error that "code_interpreter" is not in the AgentConfig's tools field" but the code_interpreter is not really necessary as it is not needed in Llama3.1-8B.

client log:

inference> assistant<|end_header_id|>

Switzerland is a beautiful country with a rich history, stunning mountains, and vibrant cities. Here are three must-visit places in Switzerland:

1. **Geneva**: Geneva is a global hub for international diplomacy and is often referred to as the "City of Peace". It's home to ...

These are just a few examples of Switzerland's amazing attractions!
500: Internal server error: An unexpected error occurred. Tool code_interpreter not found
inference> brave_search.call(query="what is special about #1")...

Showing the real error in the client: Tool code_interpreter not found

Sources

Please link relevant resources if necessary.

Before submitting

• [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• [X] Ran pre-commit to handle lint / formatting issues.
• [X] Read the contributor guideline, Pull Request section?
• [ ] Updated relevant documentation.
• [ ] Wrote necessary unit or integration tests.

[chuenlok]

@yanxi0830 Can you help review this?

[yanxi0830]

Thanks! Left some questions. Could you rebase the change on top of current main? There have been some refactors done on the agents lib.

[chuenlok]

Thanks! Left some questions. Could you rebase the change on top of current main? There have been some refactors done on the agents lib.

Rebased!