Fixes #63: Implement Customizable Model Selection

[ahmad2b]

This PR implements flexible model selection system, allowing users to switch between OpenAI and Anthropic models while maintaining a consistent user experience.

Key technical aspects:

• Model Selection Pattern: New abstraction layer in lib.ts that provides uniform interface for different AI models
• Type-Safe Integration: Strict typing for model names and configurations using TypeScript literal types
• Stateful Model Management: Thread-level model persistence with automatic state handling
• Seamless UX: ChatGPT-style model switching with automatic thread management

https://github.com/user-attachments/assets/5d7653f3-e0ff-462b-a914-24bcd0f54329

Changes Made

New Files

• src/agent/lib.ts - Core model abstraction and selection implementation

Modified Files

Core Changes

• src/open-canvas/index.ts, src/agent/open-canvas/state.ts

  • Added model state management and type definitions

• Updated model implementation across agent nodes in src/agent/open-canvas/nodes/*

  • Refactored chat model initialization using new pattern

UI/UX Updates

• New ModelSelector.tsx component
• Updated hooks (useGraph.tsx, useThread.tsx) with model state support
• Updated canvas and primitives components for model integration

Testing

Tested with:

• Anthropic API integration
• OpenAI API integration
• Verified model switching functionality
• Thread preservation and recreation

Please let me know if any changes or additional information is needed.

Fixes #63

[vercel[bot]]

@ahmad2b is attempting to deploy a commit to the LangChain Team on Vercel.

A member of the Team first needs to authorize it.

[ahmad2b]

Thank you @bracesproul for the detailed review! I appreciate the clear guidance. I’ll revise the PR to:

• Utilize the existing initChatModel class from Langchain
• Add support for the specified models
• Move model selection to configurable fields instead of state
• Keep the original models for tool-calling nodes

No worries about the spec; I’m excited to implement these changes and will push the updates soon. Thanks again!

[bracesproul]

Great! Very excited to review again once ready. Please just dismiss my change request review & re-request. Thanks!

[ahmad2b]

Hi @bracesproul! I’ve created a new PR (#136 ) for the requested changes to avoid conflicts with the main branch, as the main branch had substantial updates that would make merging challenging. All changes and improvements are now reflected there. Closing this PR to keep everything organized. Thank you for the guidance!