Compression should be a forking lifecycle event, not a destructive rewrite

When an agent’s context fills up, the common move is to summarize older turns in place — destroying the originals. Hermes instead treats each compression as a fork: it closes the current session, seeds a child session with the summary, rotates the session ID, and records parent-child lineage, so a long conversation becomes a lineage chain rather than one repeatedly rewritten transcript. This is a direct structural answer to how Reasoning evaporation permanently destroys agent decision chains when the context window closes — the pre-summary detail stays recoverable instead of vanishing once the window closes. It sits in productive tension with Evolving summaries beat append-only memory — rewrite profiles, don't accumulate facts: rewrite the working summary for the live context, but keep the lineage so nothing is silently lost — all still operating under the hard limit that The context window is the fundamental constraint — everything else follows. Treating compression this way is what lets Sessions are runtime infrastructure, not just resumable transcripts rather than disposable scratchpads.