nav-advance_skill

Overview

This skill advances the agent forward up to N blocks using navigation conventions that preserve verification and history. It performs single-step moves with automatic alignment and stops early on collisions, falls, or ambiguous support. The result includes a clear success or failure status and a brief summary of steps completed.

How this skill works

Before moving, the agent is snapped to the nearest block center and cardinal yaw to ensure predictable direction and avoid fractional-offset collisions. The skill performs up to the requested number of single-block moves, verifying landing, snapping to center after each move, and updating navigation history. It halts immediately on unsafe conditions such as collisions, unexpected vertical changes, loss of support, observation failures, or falls and returns a failure reason.

When to use it

• Advance multiple blocks reliably without writing planner loops.
• Execute forward motion when you need verification after each step.
• Move while preserving nav history and grid alignment for later recovery.
• Stop on safety events (collision or fall) without continuing blind motion.
• When you require consistent cardinal-directed movement after using nav-turn.

Best practices

• Ensure agent yaw points in the desired direction before calling (use nav-turn).
• Request a modest step_duration to balance speed and observation reliability.
• Treat a FELL failure as a safety event and consider calling nav-backtrack.
• Check returned reason and value to decide recovery or replanning actions.
• Avoid relying on this skill for diagonal or non-cardinal movement.

Example use cases

• Move forward three blocks along a hallway after aligning yaw with nav-turn.
• Cross a sequence of predictable, flat blocks while ensuring each step is verified.
• Advance toward an object while stopping immediately on unexpected collisions.
• Perform grid-aligned traversal prior to a perception or manipulation action.
• Use as a robust building block inside higher-level planners instead of looping nav-move.