medium severityLangChain ChatPerplexity
Citations present in raw Perplexity API response['citations'], but missing when using LangChain ChatPerplexity; only response.content with [1][2] markers shows, no source list.[LangChain GitHub #28108](https://github.com/langchain-ai/langchain/issues/28108)
Root cause
LangChain's ChatPerplexity did not pass the Perplexity-specific 'model_extra' field (containing citations array) to AIMessage; only content was forwarded.[LangChain GitHub #28108](https://github.com/langchain-ai/langchain/issues/28108)
Perplexity APILangChaincitationsmodel_extraChatPerplexity