Scene Verifier

Scene Verifier provides the robonix/service/verifier/verify contract for planar navigation. After a configured navigation capability succeeds, Executor invokes this provider to compare the navigation goal with the robot pose reported by robonix/system/scene/get_robot_context.

The verifier supports robonix/service/navigation/navigate goals in the map frame. It uses Scene observations instead of trusting the navigation output as evidence that the robot reached its goal.

Deployment

Merge the service entry and verification rule below into the existing service list and system.executor mapping in the deployment manifest.

system:
  executor:
    verification:
      overlap: true
      rules:
        - target_contract_id: robonix/service/navigation/navigate
          target_provider_id: nav2
          verifier_provider_id: scene_verifier
          verifier_args:
            scene_provider_id: scene
            check_yaw: true

service:
  - name: scene_verifier
    path: ../../services/verifiers/scene_verifier
    config:
      distance_tolerance_m: 0.5
      yaw_tolerance_rad: 0.35
      observation_timeout_s: 5.0

Starting the provider alone does not enable verification. Executor invokes it only when a successful capability call matches a verification rule.

Service configuration

Position and yaw errors must be strictly less than their configured tolerances. An error equal to its tolerance fails verification.

Verification rule arguments

When check_yaw is enabled, the goal must contain a valid planar unit quaternion. An identity quaternion represents zero yaw. When check_yaw is disabled, the verifier does not require or inspect the goal orientation.

When expected_map_id is omitted, Scene must still report a non-empty map ID, but the verifier cannot establish which map the original goal came from.

Verification behavior

Verification passes when all enabled checks succeed:

• Scene reports a known, current robot pose and a non-empty map ID.
• The observed position is within distance_tolerance_m of the goal.
• The observed yaw is within yaw_tolerance_rad when check_yaw is enabled.
• The observed map ID matches expected_map_id when one is configured.

Unknown or stale poses, map mismatches, and errors outside the configured tolerances produce passed=false. Invalid requests, malformed Scene responses, and Atlas or MCP failures make verification unavailable. Executor converts both outcomes into a failed capability result and preserves the original result only when verification passes.

Limitations

• Only planar goals with goal.header.frame_id set to map and a zero z coordinate are supported.
• map_id identifies a map, while frame_id identifies a coordinate frame; they are not interchangeable.
• Scene does not report a separate coordinate frame for the robot pose. The verifier relies on Scene's map-frame snapshot convention.
• Freshness is determined from Scene's stale field. Host and simulation clocks are not compared.
• Each request reads one Scene snapshot. The verifier does not retry, wait for further movement, or subscribe to ROS topics.
• observation_timeout_s applies to the asynchronous MCP observation. Executor applies its own deadline to the complete verification request.

Build and test

With uv and rbnx available, run from the repository root:

rbnx validate services/verifiers/scene_verifier
rbnx build -p services/verifiers/scene_verifier

The build generates the verifier_mcp module. Do not edit generated files by hand.

The unit tests do not require Atlas or ROS 2:

cd services/verifiers/scene_verifier
python3 -m unittest discover -s tests -v

For an end-to-end check, start a deployment containing Executor, Atlas, Scene, and this provider. Inspect the correlated logs with:

rbnx logs -t scene_verifier
rbnx logs -t executor