Claude does not check if tool/software is already installed before attempting reinstall

Bug Report

Category: waste (unnecessary resource consumption)
Severity: Major
Claude Code Version: 2.1.84
OS: Windows 11 Pro

Description

Claude Code does not verify whether a tool/software is already installed on the system before attempting to download and install it again. In the same session:

1. User needed gh CLI - Claude found it's not in bash PATH
2. Claude downloaded gh_2.74.0_windows_amd64.zip (~50MB), extracted it to a temp folder
3. It worked from the extracted path
4. 10 minutes later, a find command revealed gh.exe was already installed at C:\Program Files\GitHub CLI\gh.exe AND authenticated

Expected Behavior

Before any installation attempt, Claude should:

1. Run find / where.exe / Get-Command to search common paths
2. Check standard locations (C:\Program Files\, %APPDATA%, etc.)
3. Only install if the tool is genuinely not found

Actual Behavior

Claude skips the verification step entirely and goes straight to download + install. When gh was not found via bare gh command in bash, Claude assumed it was not installed instead of searching with full paths.

Steps to Reproduce

1. Have a tool installed in a standard location (e.g., C:\Program Files\GitHub CLI\gh.exe)
2. Ensure it's NOT in the bash PATH (common on Windows with Git Bash)
3. Ask Claude to use the tool
4. Claude will attempt to install it again instead of finding the existing installation

Impact

• ~5 minutes wasted on unnecessary download + extract
• ~50MB disk space wasted (duplicate installation)
• ~500+ tokens wasted on download/extract commands
• User frustration

Suggested Fix

Add a "check before install" pattern:

# Before any install, search for existing installation
existing=$(find /c/Program\ Files /c/Program\ Files\ \(x86\) -name "tool.exe" -type f 2>/dev/null | head -1)
if [ -n "$existing" ]; then
    echo "Found existing installation: $existing"
else
    echo "Not found, proceeding with install..."
fi

This applies to any tool installation: gh, node, python, java, etc.