library_interop

Library Interoperability Examples

This directory demonstrates how to integrate Mellea with other LLM libraries and frameworks.

Files

langchain_messages.py

Shows how to convert LangChain messages to Mellea format and use them in a session.

Key Features:

• Converting LangChain messages to Mellea messages
• Using OpenAI-formatted messages as an intermediate format
• Building Mellea contexts from external message formats
• Maintaining conversation history across libraries

Concepts Demonstrated

• Message Conversion: Translating between different message formats
• Context Building: Creating Mellea contexts from external data
• Library Integration: Using Mellea alongside other frameworks
• Format Compatibility: Working with OpenAI-compatible message formats

Basic Pattern

from langchain_core.messages import HumanMessage, AIMessage, SystemMessage
from langchain_core.messages import convert_to_openai_messages
from mellea.stdlib.components import Message
from mellea.stdlib.context import ChatContext
from mellea import start_session

# 1. Get messages from another library
messages = [
    SystemMessage(content="You are a helpful assistant"),
    HumanMessage(content="Hello!"),
    AIMessage(content="Hi there!")
]

# 2. Convert to OpenAI format (if needed)
messages = convert_to_openai_messages(messages=messages)

# 3. Build Mellea context
ctx = ChatContext()
for msg in messages:
    ctx = ctx.add(Message(role=msg["role"], content=msg["content"]))

# 4. Use in Mellea session
m = start_session(ctx=ctx)
response = m.chat("What was the last assistant message?")

Integration Tips

• OpenAI Format: Many libraries support OpenAI message format as a common interchange
• Explicit Contexts: Mellea uses explicit context objects - build them from external messages
• Additional Data: If messages contain images, documents, or other data, extract those fields explicitly
• Bidirectional: You can also convert Mellea messages back to other formats

Supported Libraries

This pattern works with any library that can export to OpenAI-compatible format:

• LangChain
• LlamaIndex
• Haystack
• Semantic Kernel
• And many others

Related Documentation

• See mellea/stdlib/components/chat.py for Message API
• See mellea/stdlib/context.py for context management