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Issue: Mock Mode Should Not Depend on Robot Hardware Topics

Date: October 12, 2025
Status: Open
Priority: Medium
Labels: bug, mock-mode, ros2, agent

Problem

When running ./start.sh --mock --agent-only, the mission agent stalls waiting for ROS topics that don't exist:

[mission_agent-1] INFO:unitree_hardware_interface_video:ROSVideoProvider initialized
[mission_agent-1] 2025-10-12 12:41:13,181 - dimos.robot.ros_control - INFO - Subscribing to camera/compressed with BEST_EFFORT QoS using message type CompressedImage
[mission_agent-1] 2025-10-12 12:41:13,182 - dimos.robot.ros_control - INFO - Subscribing to go2_states with BEST_EFFORT QoS

The agent hangs here indefinitely, waiting for topics that will never be published in mock mode.

Root Cause Analysis

Current Behavior

The mission agent initializes UnitreeROSControl which subscribes to: 1. camera/compressed - Camera feed from robot 2. go2_states - Robot state messages

Even in mock mode, these subscriptions are created and the agent waits for them before continuing initialization.

Why This Is a Problem

  1. Mock mode should be hardware-independent - Should work for development/testing without any robot hardware
  2. Agent-only mode should not need driver - --agent-only flag implies no driver is running
  3. Camera topic doesn't exist yet - We don't publish to camera/compressed anywhere in our code currently
  4. Blocks testing - Can't test agent, LLM integration, or embeddings without robot hardware

Code Locations

File: src/shadowhound_mission_agent/shadowhound_mission_agent/mission_executor.py - Lines ~150-180: Robot initialization with UnitreeROSControl - No conditional logic for mock mode

File: src/dimos-unitree/dimos/robot/unitree/unitree_ros_control.py - Unconditionally subscribes to topics even when mock_connection=True

Expected Behavior

Mock Mode Behavior

When MOCK_ROBOT=true or --mock flag is used:

  1. No ROS topic subscriptions - Don't subscribe to hardware topics
  2. Mock video provider - Use dummy/test images instead of camera feed
  3. Mock robot state - Generate fake odometry/state data
  4. Fast initialization - Agent should start immediately

Agent-Only Mode

When --agent-only flag is used:

  1. No driver dependency - Don't wait for driver topics
  2. Optional robot connection - Can run with or without robot
  3. Graceful degradation - Work with whatever topics are available

Proposed Solutions

Modify UnitreeROSControl to check mock mode:

# In unitree_ros_control.py
def __init__(self, mock_connection=False, ...):
    self.mock_connection = mock_connection

    if not self.mock_connection:
        # Only subscribe to real topics in non-mock mode
        self._setup_ros_subscriptions()
    else:
        # Mock mode: use dummy providers
        self._setup_mock_providers()

Pros: - Clean separation of concerns - Easy to maintain - Works for both mock and real modes

Cons: - Requires changes to DIMOS (submodule) - Need to track in development policy

Option 2: Mock Topic Publishers

Create a mock driver that publishes dummy data:

# In start.sh --mock mode
ros2 topic pub /camera/compressed sensor_msgs/CompressedImage "{}" &
ros2 topic pub /go2_states ... &

Pros: - No code changes needed - Tests ROS communication path

Cons: - Hacky workaround - Extra processes to manage - Still couples mock mode to ROS topics

Option 3: Timeout-Based Initialization

Make topic subscriptions non-blocking with timeouts:

# Wait for topics with timeout
if not self.mock_connection:
    self._wait_for_topics(timeout=5.0)
else:
    # Mock mode: skip waiting
    pass

Pros: - Simple change - Backwards compatible

Cons: - Still creates subscriptions (unnecessary in mock) - Adds latency even in mock mode

Phase 1: Quick Fix (Immediate)

  1. Add timeout to topic waiting in mock mode
  2. Use dummy video/state providers when topics unavailable
  3. Log warnings but continue initialization

Time: 1-2 hours
Risk: Low
Impact: Unblocks testing now

Phase 2: Proper Solution (Follow-up)

  1. Refactor UnitreeROSControl with conditional subscriptions
  2. Create proper mock providers for video/state
  3. Add unit tests for mock mode
  4. Document mock mode architecture

Time: 4-6 hours
Risk: Medium (submodule changes)
Impact: Clean, maintainable solution

Additional Context

Current Mock Mode Issues

  1. Camera topic: We log "Subscribing to camera/compressed" but:
  2. This topic is never published in our code
  3. Go2 SDK might publish it, but we haven't verified

  4. Mock mode definitely won't have it

  5. State topics: We subscribe to go2_states which:

  6. Comes from go2_robot_sdk driver
  7. Only exists when driver is running

  8. Not available in --agent-only mode

  9. Agent-only semantics: The --agent-only flag should mean:

  10. Skip launching driver
  11. Work without driver topics
  12. Test agent logic in isolation

Testing Workarounds

Until fixed, test embeddings/LLM without full agent:

# Use standalone test script
python3 test_embeddings_fix.py

# Or run agent with driver (even in mock)
./start.sh --mock  # Without --agent-only
  • None yet (first issue for mock mode)
  • docs/dimos_development_policy.md - Submodule modification policy
  • docs/local_ai_implementation_status.md - Testing strategy
  • .github/copilot-instructions.md - Development patterns

Acceptance Criteria

  • [ ] ./start.sh --mock --agent-only starts successfully
  • [ ] Agent initializes without waiting for hardware topics
  • [ ] Mock video provider works (dummy images or test video)
  • [ ] Mock robot state provider works (fake odometry)
  • [ ] No blocking waits for non-existent topics
  • [ ] Tests pass in CI without hardware
  • [ ] Documentation updated

Notes

This blocks: - ✅ Testing local embeddings fix (workaround: use test_embeddings_fix.py) - ✅ Testing LLM integration without hardware - ✅ CI/CD without robot hardware - ✅ Development without access to robot

This is a common pattern we should solve properly for long-term maintainability.