Coding agent's shell tool returns garbled Japanese (mojibake) in command output on Windows

On Windows, Japanese text printed by a command executed through the CLI agent's run_shell_command tool came back to the agent as mojibake, while the same command displayed correctly in a local PowerShell terminal. A later report on a newer CLI version said the bug still occurred; the issue was closed citing a user-side code-page workaround after two proposed fixes were closed without merging.

Framework / agent

Gemini CLI · CLI coding agent

Remediation attempts

FAILEDSUGGESTEDSUGGESTEDSUGGESTED

Recurrence

not documented

Source languages

en, ja

Updated

2026-09-30

Sources

• GITHUB ISSUE Bug Report: run_shell_command output is garbled for Japanese characters on Windows — github.com/google-gemini/gemini-cli, retrieved 2026-09-29
• GITHUB PULL REQUEST fix(core): force utf8 encoding in pty to fix multibyte character output is garbled issue — github.com/google-gemini/gemini-cli, retrieved 2026-09-29
• GITHUB PULL REQUEST feat(core): add 'encoding' parameter to run_shell_command and improve Windows encoding detection — github.com/google-gemini/gemini-cli, retrieved 2026-09-29

Symptoms

• Japanese characters in stdout of a command run via run_shell_command are returned as garbled text
• The same command shows Japanese correctly when run directly in PowerShell or Command Prompt on the same machine
• The problem was still reported on a later CLI version with PowerShell 7.5

Similarity to your system is not implied. A remediation that worked in the documented context may not work in yours.