Upgrade Cohere integration

[andreibondarev]

• Bump up cohere gem to ~> 1.0.1
• Enable Assistant support for Cohere

[Copilot]

Pull Request Overview

This PR upgrades the Cohere integration by bumping the cohere gem version to ~> 1.0.1 and enabling assistant support for Cohere. Key changes include:

• Updating response parsing in CohereResponse to match the new Cohere API schema.
• Adjusting the embed and chat methods in the Cohere wrapper.
• Introducing CohereMessage and a new Cohere adapter in the assistant module to support tool calls and message formatting.

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
lib/langchain/llm/response/cohere_response.rb	Adjusts response parsing and token calculation methods to conform with Cohere API changes.
lib/langchain/llm/cohere.rb	Upgrades the gem version and revises parameter handling in embed and chat methods.
lib/langchain/assistant/messages/cohere_message.rb	Introduces a new message class for Cohere with support for tool calls and role handling.
lib/langchain/assistant/llm/adapters/cohere.rb	Adds a Cohere adapter, including chat parameter construction and tool build logic.
lib/langchain/assistant/llm/adapter.rb	Updates the adapter selection logic to include the new Cohere adapter.
langchain.gemspec	Bumps the development dependency for cohere-ruby to ~> 1.0.1.

Comments suppressed due to low confidence (1)

lib/langchain/llm/cohere.rb:88

• The removal of the mandatory check for an empty messages argument may lead to unexpected behavior if an empty array is passed. Consider adding validation to ensure that messages are provided.

def chat(params = {})

[Copilot]

Consider providing a default value for the 'parallel_tool_calls' parameter to avoid a potential ArgumentError when it is not supplied.