Windows: `isInstalled()` always returns false even when OpenCode is on PATH

[Alcatraz-Zhang]

Short description

Windows: isInstalled() always returns false even when OpenCode is on PATH

What happened?

On Windows, running npx @cortexkit/magic-context@latest setup --harness opencode reports "OpenCode host not found on PATH" even when OpenCode is correctly installed and discoverable via where.exe opencode.

Root cause: isInstalled() in packages/cli/src/adapters/opencode.ts uses two detection strategies, both of which fail on Windows:

1. process.env.HOME — typically undefined on Windows (should use os.homedir() or USERPROFILE)
2. execSync("command -v opencode") — this is a Bash built-in that does not exist in PowerShell/CMD, so it always throws, causing isInstalled() to return false unconditionally on Windows.

Expected behavior: OpenCode is detected correctly on Windows, e.g. by falling back to where.exe opencode or using execSync("where opencode") when process.platform === "win32".

Steps to reproduce:

1. Install OpenCode on Windows so it is available on PATH (e.g. via bun — C:\Users\<user>\.bun\bin\opencode.exe)
2. Confirm with where.exe opencode — returns the correct path
3. Run npx @cortexkit/magic-context@latest setup --harness opencode
4. Setup reports: "OpenCode host not found on PATH. Install OpenCode: curl -fsSL https://opencode.ai/install | bash."

Suggested fix:

isInstalled(): boolean {
    if (existsSync(join(homedir(), ".opencode", "bin", "opencode"))) return true;
    const cmd = process.platform === "win32" ? "where opencode" : "command -v opencode";
    try {
        execSync(cmd, { stdio: "ignore" });
        return true;
    } catch {
        return false;
    }
}

Diagnostics

N/A

Plugin version

No response

OpenCode version

No response

Platform

Windows x64

Client

OpenCode TUI (CLI)

Log output (optional)

[Vulcankta]

The isInstalled() method could be replaced entirely with the same approach already used in doctor (isOpenCodeInstalled() → execSync("opencode --version")), which works cross-platform and doesn't have the HOME or command -v issues. The current code has two different detection strategies (isInstalled() for setup, isOpenCodeInstalled() for doctor) doing the same job with inconsistent platform support — unifying them would fix the Windows bug and reduce code duplication.