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Sweep 22 Oct 2026 · 21:04Z Build v2.1.309 528 read Stable v2.1.308 Latest v2.1.309 Next v2.1.309 Feeds RSS JSON llms.txt llms-full.txt Unofficial

Claude Code v2.1.269 ·

New Windows shell launcher for PowerShell/cmd, switchable via env var

Bash commands on Windows can now run through a dedicated PowerShell/cmd launcher, on by default but switchable off

Group of 2 Use it now Improvements
JSON All of v2.1.269
Use it nowTier: how much it should matter to you
3Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
Bash ToolArea: what it touches
ImprovementsKind: in v2.1.269,
What probably matters to youSection of the release

Unclear Whether this launcher path is enabled for any user is unknown, since the tengu_parallel_trinket gate is unread for this release.

What

  • Bash tool subprocess spawning on Windows can now route through a dedicated PowerShell/cmd launcher, using fixed stdio and windowsVerbatimArguments settings, instead of the normal stdio setup. When the launcher's process id is resolved, a shell_windows_launcher telemetry event is recorded.
  • The launcher spawns PowerShell commands through a cmd.exe wrapper script that writes output to a temp file and sets the console codepage to UTF-8 (chcp 65001), instead of spawning PowerShell directly.
  • It is on by default via a feature-flag resolver but can be disabled with an environment variable (CLAUDE_CODE_DISABLE_WINDOWS_SHELL_LAUNCHER). If it fails, Claude Code falls back to spawning directly, with telemetry reasons such as flag_off, env_opt_out, cmd_unavailable, cmd_probe_timeout, and unsafe_shell_path.

Why This changes how Bash commands are executed on Windows to work around PowerShell spawning quirks, while keeping an escape hatch and fallback path for cases where the new launcher doesn't work.

How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtWhether this launcher path is enabled for any user is unknown, since the tengu_parallel_trinket gate is unread for this release.
The name it cites is new in this buildNew in this build: tengu_parallel_trinket

See this entry in the whole of v2.1.269 →

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