Claude Code v2.1.170: Claude Fable 5 Model Access and VS Code Session Fix

Claude Code v2.1.170 introduces Claude Fable 5, a new Mythos-class model that Anthropic has deemed safe for general use. According to the release, Fable's capabilities exceed those of any model previously made generally available. The update also fixes a session-saving bug affecting VS Code integrated terminal users.

Key Changes

• Claude Fable 5 (Mythos-class): New high-capability model, safer for general deployment. Capabilities surpass all prior generally available models. Requires updating to v2.1.170 for access.
• Session Transcript Fix: Sessions launched from the VS Code integrated terminal (or any shell inheriting Claude Code environment variables) were not saving transcripts and failed to appear in --resume output. This is now fixed.

Getting the Update

Update Claude Code to version 2.1.170 to access Claude Fable 5. If you're using VS Code's integrated terminal, the session fix is especially relevant — your transcripts will now persist correctly.

Who This Affects

All Claude Code users interested in evaluating new models, and anyone relying on --resume for session continuity, particularly those using VS Code or custom shell environments that propagate Claude Code env vars.