Hmbown/CodeWhale · error · anyhow::Error

Sub-agents run in the background and cannot use Bash with in

Error message

Sub-agents run in the background and cannot use Bash with interactive=true because that would take over the parent TUI terminal. Use Bash without interactive, or with background=true / tty=true, or task_shell_start instead.

What it means

Error "Sub-agents run in the background and cannot use Bash with interactive=true because that would take over the parent TUI terminal. Use Bash without interactive, or with background=true / tty=true, or task_shell_start instead." thrown in Hmbown/CodeWhale.

Source

Thrown at crates/tui/src/tools/subagent/mod.rs:15172

    };
    raw_paths
        .into_iter()
        .map(|path| normalize_claim_path(&path).map_err(anyhow::Error::msg))
        .collect()
}

fn reject_subagent_terminal_takeover(name: &str, input: &Value) -> Result<()> {
    let wants_interactive_shell = matches!(name, "bash" | "Bash" | "exec_shell")
        && input
            .get("action")
            .and_then(Value::as_str)
            .is_none_or(|action| action == "run")
        && input
            .get("interactive")
            .and_then(Value::as_bool)
            .unwrap_or(false);
    if wants_interactive_shell {
        return Err(anyhow!(
            "Sub-agents run in the background and cannot use Bash with interactive=true \
             because that would take over the parent TUI terminal. Use Bash without \
             interactive, or with background=true / tty=true, or task_shell_start \
             instead."
        ));
    }
    Ok(())
}

/// Resolve the effective allowed-tools list for a child.
///
/// **v0.6.6 default: full inheritance.** Returning `Ok(None)` means the
/// child sees the same tool surface as the parent's Agent mode — every
/// family including `with_subagent_tools` so it can recurse. The narrowing
/// path (`Ok(Some(list))`) is only used by:
/// - `Custom` agent types (which require an explicit list).
/// - Callers that pass `explicit_tools` (advanced / legacy use).
///

View on GitHub (pinned to 0c42157ee5)

Solutions

1. Call the Bash tool without the interactive flag to run a normal one-shot shell command.
2. Set background=true on the Bash call to run the command without attaching to the parent TUI's terminal.
3. Set tty=true on the Bash call if a pseudo-terminal is needed, without interactive ownership.
4. Use the task_shell_start tool to run an interactive shell as a managed background task the sub-agent can poll.

When it happens

Trigger: Thrown at crates/tui/src/tools/subagent/mod.rs:15172 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of Hmbown/CodeWhale@0c42157ee5 (2026-08-20). Data as JSON: /api/errors/d1654883cfa11f6f. Report an issue: GitHub.