Bugfix/LLM node issues for Claude Opus 4.5 and Claude Sonnet 4.5

[tianwei-liu]

Fixes #5586

1. Installed @llamaindex/anthropic lib to support new Claude models. Doc
2. Langchain sets topP to -1 by default, which is invalid for Claude Opus 4.5 and Claude Sonnet 4.5. The fix ensures the invalid default is removed before making API calls.

[gemini-code-assist]

Summary of Changes

Hello @tianwei-liu, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses critical compatibility issues with the new Claude Opus 4.5 and Sonnet 4.5 models. It integrates the dedicated @llamaindex/anthropic library to provide proper support for these models and resolves a specific problem where an invalid default topP parameter from Langchain was preventing successful API interactions. The changes ensure robust and correct functionality when utilizing these advanced Anthropic models.

Highlights

• New Anthropic Library Integration: The @llamaindex/anthropic library has been installed to enable support for the latest Claude models, including Opus 4.5 and Sonnet 4.5.
• topP Parameter Correction: A bug where Langchain's default topP value of -1 was causing issues with Claude Opus 4.5 and Sonnet 4.5 has been fixed by ensuring this invalid default is removed before API calls.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This pull request addresses a bug with new Claude models (Opus 4.5 and Sonnet 4.5) where an invalid default value for topP was being sent. The changes include adding the @llamaindex/anthropic dependency, updating the corresponding import, relaxing the modelName type for better flexibility, and adding logic to handle the invalid topP default from Langchain. The changes are logical and effectively resolve the issue. I have one suggestion to improve the robustness of the fix.

[HenryHengZJ]

Agentflow is using ChatAnthropic from langchain, not llamaindex. We're also deprecating and stop updating llamaindex, I think we can remove the update in this PR

[tianwei-liu]

Test it locally. The bug will be fixed by replacing import { Anthropic } from 'llamaindex' with import { ChatAnthropic } from '@langchain/anthropic' in ChatAnthropic_LlamaIndex.ts, without further code change about unset topP. Since we are deprecating llamaIndex, I'll close this PR.