Claude Code v2.1.257
Claude Code v2.1.257 was released on .
Summary
Claude Code 2.1.257 now includes Claude Fable 5.1 as the default model with expanded context and improved pricing, plus new customizable time format settings for your timestamps. We've also strengthened security with stricter containment rules that require explicit approval fo...
Release Context
- This was the 204th Claude Code release of 2026 tracked by Havoptic.
- It shipped 1 day after Claude Code v2.1.252 (August 31, 2026).
- Claude Code: ships every 0.9 days — 30 releases in the last month.
Why it matters: One million token context now standard.
With Fable 5.1, our team has taken on more ambitious projects that would have previously taken months. What big bets do you want to take? Ask Fable 5.1 in Claude Code, Claude Cowork, Claude Tag to… — cat
Shipped around the same time
Within 3 days of this release, other AI coding tools also shipped:
- GitHub Copilot CLI v1.0.83 (September 4, 2026)
- Antigravity CLI v1.1.26 (September 4, 2026)
- OpenAI Codex CLI rust-v0.153.2 (September 3, 2026)
- OpenAI Codex CLI rust-v0.153.1 (September 3, 2026)
- Antigravity CLI v1.1.25 (September 3, 2026)
Compare Claude Code: vs OpenAI Codex CLI · vs Cursor · vs Gemini CLI · vs Kiro CLI · vs GitHub Copilot CLI · vs Devin Desktop · vs Antigravity CLI · vs Grok Build
Release Notes
- Added Claude Fable 5.1 (claude-fable-5-1), now the default Fable model — 1M context, $10/$50 per Mtok with $0.25/Mtok cache reads
- Added "Time format" (timeFormat) and timeZone settings: 12-hour, 24-hour, 24-hour UTC, or a strftime pattern for the turn-end clock and transcript-view timestamps
- Added a Containment Escape rule to auto mode so cloud metadata-credential fetches, egress evasion, and cross-tenant reach are no longer auto-approved unless your environment marks them expected
- Added CLAUDECODESUBAGENTMODELFORCE to apply CLAUDECODESUBAGENTMODEL (or the main model) to every subagent, ignoring per-spawn and agent-definition model overrides
- Added s in /effort to change effort for the current session only, matching /model
- Added a /doctor warning for stale sandbox mask files left by a killed session
- Added a one-time prompt in auto mode before the first file read outside the working directories, with the option to block such reads (permissions.blockReadsOutsideWorkingDirectories)
- Added support for a gateway-supplied description on discovered /model picker entries (CLAUDECODEENABLEGATEWAYMODELDISCOVERY); entries without one still read "From gateway"
- Fixed settings in a .claude/ folder created after startup not being picked up until restart
- Fixed sessions dispatched from an agent view opened with ← always starting in the original session's permission mode, overriding the target directory's defaultMode and the agent's permissionMode
- Fixed keybindings.json rebinds of Ctrl+G being ignored in claude agents; its Ctrl+S / Ctrl+T are now rebindable via the new Agents context
- Fixed background sessions failing to start on macOS npm installs during a self-update, and on Windows when a stale daemon lock file pointed at a reused process id
- Fixed the working spinner stopping while a response streams behind a slash-command panel
- Fixed a background session's state.json detail repeating its own dispatch prompt after a scheduled wake-up
- Fixed claude agents keeping a background session you re-prompted buried in Completed after it finished again; Completed now orders by the latest finish
- Fixed claude --bg from a directory that was just deleted reporting "backgrounded" and leaving a crashed session row; it now prints the reason and exits 1
- Fixed Remote Control connecting mid-session re-sending the Bash tool definition, causing a prompt-cache miss
Other Recent Claude Code Releases
- v2.1.263 (September 6, 2026)
- v2.1.261 (September 4, 2026)
- v2.1.260 (September 3, 2026)
- v2.1.259 (September 2, 2026)
- v2.1.251 (August 28, 2026)
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