1545 Requirements 908b8494

Requirements: Task Mode Default

Metadata

• Feature: task-mode-default
• Status: APPROVED
• Created: 2026-02-05
• Author: /zerg:plan

1. Problem Statement

Currently, /zerg:rush uses auto-detection logic that selects container mode when a devcontainer is configured and built. The user wants:

1. Task mode as the default — always use Task tool subagents unless explicitly overridden
2. Container mode only when explicit — --mode container must be passed; devcontainer presence is irrelevant

This simplifies the mental model: "task mode unless I say otherwise."

2. Current State Analysis

Documentation (rush.details.md lines 163-167)

Auto-detection logic:
1. If `--mode` is explicitly set → use that mode
2. If `.devcontainer/devcontainer.json` exists AND worker image is built → container mode
3. If running as Claude Code slash command → task mode
4. Otherwise → subprocess mode

Python Code (launcher_configurator.py lines 118-155)

def _auto_detect_launcher_type(self) -> LauncherType:
    devcontainer_path = self._repo_path / ".devcontainer" / "devcontainer.json"
    if not devcontainer_path.exists():
        return LauncherType.SUBPROCESS
    # Check if image exists...
    if result.returncode == 0:
        return LauncherType.CONTAINER
    return LauncherType.SUBPROCESS

Config (.zerg/config.yaml line 13)

launcher_type: subprocess

3. Functional Requirements

FR-1: Task Mode as Default in Documentation

Update rush.details.md auto-detection logic to:

Auto-detection logic:
1. If `--mode` is explicitly set → use that mode
2. Otherwise → **task mode** (default)

Remove rules 2-4 from current logic.

FR-2: Update rush.core.md / rush.md Help Text

Change:

--mode MODE  Execution mode: container|subprocess

To:

--mode MODE  Execution mode: task|container|subprocess (default: task)

FR-3: Update Python Auto-Detection

Modify launcher_configurator.py:_auto_detect_launcher_type() to always return LauncherType.SUBPROCESS. Remove the devcontainer existence check and Docker image check entirely.

def _auto_detect_launcher_type(self) -> LauncherType:
    """Auto-detect launcher type. Always returns SUBPROCESS.

    Container mode requires explicit --mode container flag.
    """
    return LauncherType.SUBPROCESS

FR-3.1: Update Unit Tests

Update tests/unit/test_launcher_configurator.py:

• test_auto_detect_no_devcontainer — keep as-is (already expects SUBPROCESS)
• test_auto_detect_with_devcontainer_and_image — change to expect SUBPROCESS (not CONTAINER)
• test_auto_detect_docker_failure_falls_back — remove or simplify (no longer relevant)
• test_create_launcher_auto_falls_back_on_network_failure — remove (no longer relevant)

FR-3.2: Update Integration Tests

Update tests/integration/test_container_launcher.py:

• Remove or simplify TestAutoDetectLauncherMode class (devcontainer presence no longer matters for auto-detect)

FR-4: Update Config Default

Change .zerg/config.yaml:

launcher_type: task  # or remove this line since task is now implicit default

4. Files to Modify

5. Acceptance Criteria

• rush.details.md shows task mode as default
• Help text shows --mode MODE Execution mode: task|container|subprocess (default: task)
• Running /zerg:rush --workers 4 uses task mode without checking devcontainer
• Running /zerg:rush --mode container uses container mode
• Running /zerg:rush --mode subprocess uses subprocess mode

6. Non-Functional Requirements

• Python code changes required to launcher_configurator.py
• Test updates required to match new behavior
• Changes should preserve container mode functionality when explicitly requested
• Backward compatible: explicit --mode flags still work

7. Out of Scope

• Removing container mode entirely (it still works with explicit --mode container)
• Changes to worker.md or other commands
• Adding "task" as a LauncherType enum in Python (task mode is prompt-only)