ultraworkers/claw-code · error · std::io::Error

PowerShell executable not found (expected `pwsh` or `powersh

Error message

PowerShell executable not found (expected `pwsh` or `powershell` in PATH)

What it means

Returned by detect_powershell_shell in the tools crate when neither pwsh nor powershell can be found. Note the implementation probes via command_exists(), which runs `sh -lc 'command -v <name> >/dev/null 2>&1'` — so detection requires a POSIX sh, and it only sees executables on the PATH that sh inherits. The error is io::Error with ErrorKind::NotFound.

Source

Thrown at rust/crates/tools/src/lib.rs:6586

    if let Some(output) = workspace_test_branch_preflight(&input.command) {
        return Ok(output);
    }
    let shell = detect_powershell_shell()?;
    execute_shell_command(
        shell,
        &input.command,
        input.timeout,
        input.run_in_background,
    )
}

fn detect_powershell_shell() -> std::io::Result<&'static str> {
    if command_exists("pwsh") {
        Ok("pwsh")
    } else if command_exists("powershell") {
        Ok("powershell")
    } else {
        Err(std::io::Error::new(
            std::io::ErrorKind::NotFound,
            "PowerShell executable not found (expected `pwsh` or `powershell` in PATH)",
        ))
    }
}

fn command_exists(command: &str) -> bool {
    std::process::Command::new("sh")
        .arg("-lc")
        .arg(format!("command -v {command} >/dev/null 2>&1"))
        .status()
        .is_ok_and(|status| status.success())
}

#[allow(clippy::too_many_lines)]
fn execute_shell_command(
    shell: &str,
    command: &str,

View on GitHub (pinned to 08106b0c37)

Solutions

1. Install PowerShell and verify the probe can see it: pwsh --version, or command -v pwsh inside `sh -l` (login shell) since that is exactly how detection runs
2. Fix PATH so the login shell resolves pwsh: export PATH="$PATH:/usr/bin" with a symlink, or add the install dir to /etc/profile.d if sh -l strips it
3. Don't request PowerShell on hosts without it — use the default bash/sh shell tool instead
4. For Windows targets, install PowerShell 7 (pwsh) so the fallback to powershell.exe is unnecessary

Example fix

# before
claw> run in powershell: Get-Location   # -> NotFound: PowerShell executable not found

# after (Ubuntu)
sudo apt-get install -y powershell     # or: brew install powershell on macOS
sh -lc 'command -v pwsh'               # verify the exact probe detection uses
claw> run in powershell: Get-Location

fn powershell_available() -> bool {
    // mirrors detect_powershell_shell's probe exactly: sh -lc 'command -v ...'
    ["pwsh", "powershell"].iter().any(|cmd| {
        std::process::Command::new("sh")
            .arg("-lc")
            .arg(format!("command -v {cmd} >/dev/null 2>&1"))
            .status()
            .is_ok_and(|s| s.success())
    })
}

if !powershell_available() { /* route to bash/sh tool instead */ }

fn detect_shell() -> &'static str {
    if powershell_available() { "pwsh" } else { "bash" }
}

match detect_powershell_shell() {
    Ok(shell) => run_in_shell(shell, command),
    Err(e) if e.kind() == std::io::ErrorKind::NotFound => {
        // fall back to the POSIX shell tool; PowerShell is simply absent
        run_in_shell("bash", command)
    }
    Err(e) => Err(e),
}

When it happens

Trigger: Invoking the PowerShell-capable shell tool (the Bash-tool family entry point at tools/lib.rs:6580 that dispatches to detect_powershell_shell) on a Linux box with no PowerShell installed, or anywhere PATH does not contain pwsh/powershell (container images, minimal CI runners, nix shells without the powershell package). Also on Windows hosts lacking a POSIX sh, since the probe itself runs through `sh -lc`.

Common situations: Debian/Ubuntu/Alpine containers without powershell installed; macOS without brew install powershell; CI runners where PowerShell is present but not on the PATH that sh -l resolves (login-shell PATH rewriting); asking the agent to run a PowerShell command by mistake on a Linux host.

Related errors

• skill source '{}' not found: {e}
• old_string not found in file
• HOME is not set (on Windows, set USERPROFILE or HOME, or use
• credentials file must contain a JSON object
• session file was removed during save (possible concurrent mo

AI-assisted analysis of ultraworkers/claw-code@08106b0c37 (2026-08-18). Data as JSON: /api/errors/c34575435e55105d. Report an issue: GitHub.