Session

What the helpers of org.llm4s.repl talk to: a client, its completion options, the conversation so far and the statistics of the last call. Set it once as a context parameter and every helper finds it:

import org.llm4s.repl.*

given Session = Session.fromConfig()       // the `llm4s.providers.provider` section of application.conf
ask("Explain variance in Scala 3 in two sentences")

A session whose client cannot be built (no application.conf, a missing API key, an unregistered provider) is still a session: every helper prints the configuration error with its troubleshooting hint and returns a failure, so a worksheet never stops on a stack trace. failure says whether that is the case.

A session is for a REPL, a worksheet or a script, not for production code: it keeps the conversation in memory, prints to the console, and its helpers are not meant to be called concurrently. Each with* method returns a new session with the same client and an empty history.