Feature/letta agent

[2mmanu]

Summary

Changes

Added a new LettaAgent implementation that integrates with the Letta runtime client. This agent:

• Implements a custom agent that extends the base Agent class
• Handles chat interactions using Letta's LocalClient

User experience

Before:

• No integration with Letta runtime available
• Limited agent implementation options

After:

• Seamless integration with Letta runtime
• Configurable model settings through LettaAgentOptions

Checklist

• I have performed a self-review of this change
• Changes have been tested
• Changes are documented

Is this a breaking change?

RFC issue number: N/A

This is not a breaking change as it adds new functionality without modifying existing behavior.

Checklist:

• Migration process documented
• Implement warnings (if it can live side by side)

Acknowledgment

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[cornelcroi]

Thanks @2mmanu for the feature request!

Rather than adding direct support for Letta in the core library, we think this would be better suited as an example in our documentation's Cookbook/Examples section (similar to our Ollama agent example).

This would provide a clear implementation guide while keeping the core library focused.