Spanda

Lesson 10 — End-to-end patrol

Goal: Combine AI safety, hardware deploy, tasks, and mission replay in one complete workflow.

Examples:

The patrol package

examples/end_to_end/safe_patrol/ is a full project:

safe_patrol/
  spanda.toml
  src/main.sd

It demonstrates:

Hardware profile + deploy
AI planner with safety.validate() gate
Periodic watchdog task
Behavioral verify { } block

spanda check examples/end_to_end/safe_patrol/src/main.sd
spanda verify examples/end_to_end/safe_patrol/src/main.sd --target RoverV1
spanda run examples/end_to_end/safe_patrol/src/main.sd

Record and replay a mission

Mission traces capture scheduler events and robot state for regression and incident review:

# Record
spanda sim examples/end_to_end/replay_mission.sd --record

# Inspect
spanda replay replay_mission.trace

# Re-run source and verify frame parity
spanda replay replay_mission.trace --deterministic

# Play back recorded state without re-executing logic
spanda replay replay_mission.trace --playback --from T+00:01

See replay.md. Golden traces can be committed under examples/ per .gitignore rules.

Digital twins (preview)

Twin blocks mirror physical state for simulation and divergence detection:

twin Shadow {
  replay true;
  mirror pose;
}

Used in replay_mission.sd and showcase demos. Full guide: examples/showcase/digital_twin_demo.sd.

Capstone checklist

You have completed Spanda 101 when you can:

Write a robot with sensors, safety, and behaviors
Type-check and run in simulation
Route AI output through safety.validate()
Declare hardware and pass spanda verify
Structure a package with spanda.toml and tests
Record and replay a mission trace

What to do next

Path	Resource
Flagship demo	killer-demo.md
Real-time contracts	realtime.md
Fleet simulation	`examples/communication/multi_robot_fleet.sd`
Language deep dive	spanda-language.md
API lookup	spanda-reference.md

More end-to-end scenarios

Full catalog: examples/end_to_end/README.md

Scenario	Command
Warehouse delivery	`spanda verify examples/end_to_end/warehouse_delivery/src/main.sd --target RoverV1`
Pick-and-place cell	`spanda run examples/end_to_end/pick_and_place_cell/src/main.sd`
Fleet coordination	`spanda fleet run examples/end_to_end/fleet_coordination.sd`
Incident response	`spanda verify examples/end_to_end/incident_response.sd --simulate`
Real-time patrol	`spanda run examples/end_to_end/realtime_patrol.sd --trace-realtime`

Final exercise

Build a my_patrol package that:

Uses lidar + differential drive with stop_if
Includes a mock LLM planner validated through safety.validate()
Declares deploy to RoverV1 and passes spanda verify
Records a sim run and replays it with --deterministic

Compare your solution to examples/end_to_end/safe_patrol/.

Congratulations — you have finished Spanda 101.

Return to the curriculum index or explore all examples.

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