[BUG] Bash stdout not returned in VS Code Extension (Windows / Git Bash)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Date tested: 2026-03-20
Claude Code version: 2.1.80
Model: claude-sonnet-4-6
Environment: VS Code extension (not CLI)
OS: Windows 11 Pro (10.0.26200)
Shell: Git Bash — MINGW64 / MSYS2 (3.6.5-22c95533)

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Summary

When Claude Code runs Bash commands via the VS Code extension on Windows with Git Bash, stdout is never returned to Claude. Commands execute successfully but produce no visible output. File writes work correctly.

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Steps to Reproduce

1. Open Claude Code in the VS Code extension on Windows with Git Bash as the shell.
2. Ask Claude to run any command that produces stdout output, e.g.:

echo "hello"

1. Observe that the Bash tool result shows (Bash completed with no output) despite the command succeeding.

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Expected Behavior

Stdout from Bash commands should be returned to Claude as tool output, as documented and as works in the CLI version.

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Actual Behavior

All Bash commands return (Bash completed with no output) regardless of what they print to stdout. Commands do execute (side effects like file writes succeed), but stdout is never captured.

Tested commands that silently fail to return output:

• echo "hello" → no output
• date → no output
• git status → no output
• claude --version → no output

Workaround that works:

some_command > C:/Users/keith_pg85iui/_out.txt 2>&1
# then read the file with the Read tool

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Root Cause (Diagnosed)

VS Code's ConPTY (Console Pseudoterminal) leaks into the bash subprocess chain. Bash's stdout (fd 1) ends up connected to /dev/pty0 — a PTY device that Claude Code is not reading from. File writes bypass this because > file overrides fd 1 before the subprocess runs.

Evidence:

• Redirect to file + Read tool always works
• Direct stdout never works
• This is specific to the VS Code extension — the CLI version does not have this issue

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Additional Notes

• Hooks are also non-functional in VS Code extension mode (hook log files are never created), suggesting the same PTY issue affects hook execution.
• This has been reproduced across multiple Claude Code versions: first confirmed, and still present in v2.1.80 as of 2026-03-20.
• The workaround (file redirect) is functional but requires Claude to use a non-standard pattern for every single Bash command where output is needed.

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Impact

High. Claude cannot read command output normally in the VS Code extension on Windows. Every output-dependent Bash operation requires the file redirect workaround, making the VS Code extension significantly degraded compared to the CLI on this platform.

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What Should Happen?

Expected Behavior

Stdout from Bash commands should be returned to Claude as tool output, as documented and as works in the CLI version.

Error Messages/Logs

## Actual Behavior

All Bash commands return `(Bash completed with no output)` regardless of what they print to stdout. Commands do execute (side effects like file writes succeed), but stdout is never captured.

**Tested commands that silently fail to return output:**
- `echo "hello"` → no output
- `date` → no output
- `git status` → no output
- `claude --version` → no output

**Workaround that works:**

some_command > C:/Users/keith_pg85iui/_out.txt 2>&1
# then read the file with the Read tool


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Steps to Reproduce

Root Cause (Diagnosed)

VS Code's ConPTY (Console Pseudoterminal) leaks into the bash subprocess chain. Bash's stdout (fd 1) ends up connected to /dev/pty0 — a PTY device that Claude Code is not reading from. File writes bypass this because > file overrides fd 1 before the subprocess runs.

Evidence:

• Redirect to file + Read tool always works
• Direct stdout never works
• This is specific to the VS Code extension — the CLI version does not have this issue

---

Additional Notes

• Hooks are also non-functional in VS Code extension mode (hook log files are never created), suggesting the same PTY issue affects hook execution.
• This has been reproduced across multiple Claude Code versions: first confirmed, and still present in v2.1.80 as of 2026-03-20.
• The workaround (file redirect) is functional but requires Claude to use a non-standard pattern for every single Bash command where output is needed.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.80 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_