v2.1.170

Source: Anthropic Claude Code Date: 2026-06-09 URL: https://github.com/anthropics/claude-code/releases/tag/v2.1.170

Summary

Claude Code v2.1.170 introduces access to Claude Fable 5, described as a “Mythos-class model made safe for general use” with capabilities exceeding any previously generally available Anthropic model. The release also fixes a transcript-persistence bug where sessions launched from VS Code’s integrated terminal (or any shell inheriting Claude Code environment variables) would fail to save transcripts and not appear in --resume.

Implications

Feeds the capability-frontier freeze and host-ownership war threads:

• Fable 5 shipping as a Claude Code release rather than a standalone API launch is the pattern to watch. Anthropic is using the CLI as the delivery channel for frontier-tier capability, which tightens the link between tooling subscription and model access. That’s a host-ownership move: the model is most accessible through Anthropic’s own agent surface.
• “Mythos-class made safe for general use” is pointed positioning — it implies Mythos remains restricted while Fable 5 is the sanitized derivative. The capability ceiling for general-availability models just moved up; competing CLIs (Cursor, Aider, OpenCode) will need to integrate or fall behind on the raw capability axis.
• The transcript bug fix is operationally significant for any workflow running Claude Code from inside an IDE terminal — the lost-session failure mode was silent and hard to diagnose. Worth noting for anyone building automation on top of --resume flows.