Under the hood, Muse Code pairs a simple agent loop with persistent, async backg

Meta says Muse Code can resume a long task exactly where it stopped after a crash, because it writes every step of its work to a log on the user's machine. Its runtime post describes an append-only event log, a record that is only ever added to, never rewritten, holding every model call, tool run, approval and file edit in order. Meta calls the runtime replay-exact and restart-safe, meaning that the session can be rebuilt from that record and continue after a crash without losing the work done so far. The same post describes background agents that stay active through each session to avoid gathering the same information twice.

Meta's release article presents the log as the single source of truth for a session and the reason the agent can take on long tasks without being derailed by failures. Neither the post nor the article reports a recovery test, so restart safety is Meta's description of the design rather than a measured result.

Meta's current documentation, read in November, shows a limit on what a session's record can rebuild. Its rewind feature, a separate feature from crash recovery that works only with session logging switched on, rebuilds the conversation from an earlier message. It does not restore, revert or delete files in the workspace, so code changes still have to be undone with version control. The changelog for version 1.4.13 also lists fixes for cases where sessions had stopped saving their resume checkpoints, so resuming sessions has needed repairs since launch.