Bash tool's zsh shell does not source ~/.zshenv on macOS

Summary

On macOS, Claude Code's Bash tool runs commands in a zsh shell (\\$0=/bin/zsh\, \SHELL=/bin/zsh\), but that shell does not source \~/.zshenv\ at startup. This is contrary to zsh's documented behavior: \.zshenv\ is sourced for every zsh invocation unless \-f\ or \--no-rcs\ is passed.

Impact

Any PATH additions, environment variables, or bootstrap logic placed in \~/.zshenv\ (the canonical place for non-interactive shells) is silently missing from Bash tool commands. This breaks:

• Personal scripts on PATH
• Credential bootstrapping (op service account, \op inject\, etc.)
• Tool wrappers that users put in \~/.zshenv\ specifically for non-interactive contexts
• Anything that relied on zsh's documented \"sourced for all invocations\" contract

Repro

1. Add to \~/.zshenv\:

\\\sh
export PATH=\"\$HOME/bin:\$PATH\"
export MY_TEST_VAR=\"hello\"
\\\

1. Confirm interactive zsh picks it up: \zsh -c 'echo \$MY_TEST_VAR'\ prints \hello\.
2. In Claude Code, run a Bash tool call: \echo \$MY_TEST_VAR\ — prints blank.
3. \zsh -c 'echo \$MY_TEST_VAR'\ inside the Bash tool — prints \hello\ correctly, confirming the sub-invocation does source \.zshenv\ properly.

Diagnosis

The parent shell Claude Code's Bash tool uses is launched in a way that bypasses \.zshenv\. Spawning a child \zsh -c\ from within that shell works correctly, so the issue is specifically at the parent shell's init.

My theory: the shell is invoked with \--no-rcs\ or \-f\, or its \ZDOTDIR\ is set to a location without a \.zshenv\, or the PATH is reset after \.zshenv\ runs.

Workaround

Prefix commands that need \.zshenv\ state with \source ~/.zshenv && …\ or wrap in \zsh -c '…'\.

Environment

• macOS 26 (Darwin 25.5.0)
• Shell: /bin/zsh (system default)
• Claude Code: Opus 4.7 (1M context) CLI
• \.zshenv\ contains standard PATH augmentation and env bootstrap logic

Suggested Fix

Ensure the parent shell either (a) does not pass \--no-rcs\, (b) sources \.zshenv\ explicitly via \source\, or (c) documents clearly that only explicitly-exported env via the Bash tool wrapper is available, and recommends \~/.bashrc\-style init for Bash compatibility.