[BOT ISSUE] langchainrb gem not instrumented

[braintrust-bot]

Summary

The langchainrb gem is the most widely adopted Ruby AI framework (~1.1M downloads, v0.19.5, May 2025) and is not instrumented by this SDK. It is the Ruby analog of Python's LangChain, providing chat completions, embeddings, tool calling, RAG, and assistant/agent patterns across multiple providers.

What is missing

No instrumentation exists for any langchainrb execution surface. Key APIs that should be instrumented:

Chat Completions

• Langchain::LLM::*#chat(messages:, ...) — unified chat interface across all providers (OpenAI, Anthropic, Google Gemini, Ollama, AWS Bedrock, Azure OpenAI, Cohere, HuggingFace, Mistral, Replicate)
• Langchain::LLM::*#complete(prompt:, ...) — text completion

Embeddings

• Langchain::LLM::*#embed(text:, ...) — vector embeddings generation across providers

Tool / Function Calling

• Tool definitions and automatic tool execution within chat flows

Structured Outputs

• Langchain::OutputParsers::StructuredOutputParser — JSON schema-based structured extraction from LLM responses

Assistants / Agents

• Langchain::Assistant — agent framework with tool execution, conversation management, and multi-turn interaction

Braintrust docs status

not_found — No mention of langchainrb as a Ruby integration anywhere in Braintrust documentation. The SDK integrations page at https://www.braintrust.dev/docs/integrations/sdk-integrations lists a general "LangChain" integration but it is not Ruby-specific and does not cover this gem.

Upstream sources

• GitHub: https://github.com/patterns-ai-core/langchainrb
• RubyGems: https://rubygems.org/gems/langchainrb (~1.1M downloads, v0.19.5, May 2025)
• Documentation: https://rubydoc.info/gems/langchainrb

Local repo files inspected

• lib/braintrust/contrib/*/integration.rb — only 4 integrations registered: OpenAI, RubyOpenAI, RubyLLM, Anthropic. No langchainrb integration.
• lib/braintrust/contrib/ — no directory or files for langchainrb or langchain
• Appraisals — no appraisal scenarios for langchainrb
• braintrust.gemspec — no mention of langchainrb
• Grep for langchain across lib/braintrust/ returns zero matches