User vs tool

[frangarcj]

Description

This pull request addresses an issue where LLM-based agents can enter infinite loops when processing tool responses. Specifically:

1. When using Llama 3.3 70B, the React Agent would occasionally misinterpret tool responses as new user messages
2. The root cause appears to be the model's increased sensitivity to contextual details
3. The fix ensures proper identification of tool responses by adding explicit response markers

The changes are minimal but prevent potential deadlocks in agent-tool communication patterns.

Technical impact:

• Improves agent stability
• Reduces unnecessary computation cycles
• Maintains consistent conversation flow

Testing confirms the agent now correctly distinguishes between user messages and tool responses.

Fixes # (not created issue)

New Package?

Did I fill in the tool.llamahub section in the pyproject.toml and provide a detailed README.md for my new integration or package?

• Yes
• No

Version Bump?

Did I bump the version in the pyproject.toml file of the package I am updating? (Except for the llama-index-core package)

• Yes
• No

Type of Change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Your pull-request will likely not be merged unless it is covered by some form of impactful unit testing.

• I added new unit tests to cover this change
• I believe this change is already covered by existing unit tests

Suggested Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added Google Colab support for the newly added notebooks.
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I ran make format; make lint to appease the lint gods

[logan-markewich]

makes sense tbh